Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 990e7657170539ee008a3423359303a8e7c98481 / . / docs / LangRef.html
blob: 44e6fa126e029facbbfb13769acb803cbb725f66 [file] [log] [blame]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
23 <li><a href="#linkage">Linkage Types</a></li>
24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]25 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]26 <li><a href="#globalvars">Global Variables</a></li>
27 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]28 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]29 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]30 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]31 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]32 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
33 <li><a href="#datalayout">Data Layout</a></li>
34 </ol>
35 </li>
36 <li><a href="#typesystem">Type System</a>
37 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]38 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]39 <li><a href="#t_primitive">Primitive Types</a>
40 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]41 <li><a href="#t_floating">Floating Point Types</a></li>
42 <li><a href="#t_void">Void Type</a></li>
43 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]44 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]45 </ol>
46 </li>
47 <li><a href="#t_derived">Derived Types</a>
48 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]49 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]50 <li><a href="#t_array">Array Type</a></li>
51 <li><a href="#t_function">Function Type</a></li>
52 <li><a href="#t_pointer">Pointer Type</a></li>
53 <li><a href="#t_struct">Structure Type</a></li>
54 <li><a href="#t_pstruct">Packed Structure Type</a></li>
55 <li><a href="#t_vector">Vector Type</a></li>
56 <li><a href="#t_opaque">Opaque Type</a></li>
57 </ol>
58 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]59 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]60 </ol>
61 </li>
62 <li><a href="#constants">Constants</a>
63 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]64 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]65 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]66 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
67 <li><a href="#undefvalues">Undefined Values</a></li>
68 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]69 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]70 </ol>
71 </li>
72 <li><a href="#othervalues">Other Values</a>
73 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]74 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]75 </ol>
76 </li>
77 <li><a href="#instref">Instruction Reference</a>
78 <ol>
79 <li><a href="#terminators">Terminator Instructions</a>
80 <ol>
81 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
82 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
83 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
84 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
85 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
86 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
87 </ol>
88 </li>
89 <li><a href="#binaryops">Binary Operations</a>
90 <ol>
91 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]92 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]93 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]94 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]95 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]96 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]97 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
98 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
99 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
100 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
101 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
102 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
103 </ol>
104 </li>
105 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
106 <ol>
107 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
108 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
109 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
110 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
111 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
112 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
113 </ol>
114 </li>
115 <li><a href="#vectorops">Vector Operations</a>
116 <ol>
117 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
118 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
119 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
120 </ol>
121 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]122 <li><a href="#aggregateops">Aggregate Operations</a>
123 <ol>
124 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
125 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
126 </ol>
127 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]128 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
129 <ol>
130 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
131 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
132 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
133 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
134 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
135 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
136 </ol>
137 </li>
138 <li><a href="#convertops">Conversion Operations</a>
139 <ol>
140 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
141 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
142 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
143 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
144 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
145 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
146 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
147 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
148 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
149 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
150 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
151 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
152 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]153 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]154 <li><a href="#otherops">Other Operations</a>
155 <ol>
156 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
157 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
158 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
159 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
160 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
161 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
162 </ol>
163 </li>
164 </ol>
165 </li>
166 <li><a href="#intrinsics">Intrinsic Functions</a>
167 <ol>
168 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
169 <ol>
170 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
171 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
172 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
173 </ol>
174 </li>
175 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
176 <ol>
177 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
178 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
179 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
180 </ol>
181 </li>
182 <li><a href="#int_codegen">Code Generator Intrinsics</a>
183 <ol>
184 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
185 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
186 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
187 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
188 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
189 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
190 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
191 </ol>
192 </li>
193 <li><a href="#int_libc">Standard C Library Intrinsics</a>
194 <ol>
195 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]200 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
201 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
202 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]203 </ol>
204 </li>
205 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
206 <ol>
207 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
208 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
209 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
210 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]211 </ol>
212 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]213 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
214 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]215 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
216 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
217 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
218 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
219 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]220 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]221 </ol>
222 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]223 <li><a href="#int_debugger">Debugger intrinsics</a></li>
224 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]225 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]226 <ol>
227 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]228 </ol>
229 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]230 <li><a href="#int_atomics">Atomic intrinsics</a>
231 <ol>
232 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
233 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
234 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
235 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
236 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
237 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
238 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
239 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
240 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
241 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
242 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
243 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
244 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
245 </ol>
246 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]247 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]248 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]249 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]250 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]251 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]252 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]253 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]254 '<tt>llvm.trap</tt>' Intrinsic</a></li>
255 <li><a href="#int_stackprotector">
256 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]257 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]258 </li>
259 </ol>
260 </li>
261</ol>
262
263<div class="doc_author">
264 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
265 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
266</div>
267
268<!-- *********************************************************************** -->
269<div class="doc_section"> <a name="abstract">Abstract </a></div>
270<!-- *********************************************************************** -->
271
272<div class="doc_text">
273<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]274LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]275type safety, low-level operations, flexibility, and the capability of
276representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]277representation used throughout all phases of the LLVM compilation
278strategy.</p>
279</div>
280
281<!-- *********************************************************************** -->
282<div class="doc_section"> <a name="introduction">Introduction</a> </div>
283<!-- *********************************************************************** -->
284
285<div class="doc_text">
286
287<p>The LLVM code representation is designed to be used in three
288different forms: as an in-memory compiler IR, as an on-disk bitcode
289representation (suitable for fast loading by a Just-In-Time compiler),
290and as a human readable assembly language representation. This allows
291LLVM to provide a powerful intermediate representation for efficient
292compiler transformations and analysis, while providing a natural means
293to debug and visualize the transformations. The three different forms
294of LLVM are all equivalent. This document describes the human readable
295representation and notation.</p>
296
297<p>The LLVM representation aims to be light-weight and low-level
298while being expressive, typed, and extensible at the same time. It
299aims to be a "universal IR" of sorts, by being at a low enough level
300that high-level ideas may be cleanly mapped to it (similar to how
301microprocessors are "universal IR's", allowing many source languages to
302be mapped to them). By providing type information, LLVM can be used as
303the target of optimizations: for example, through pointer analysis, it
304can be proven that a C automatic variable is never accessed outside of
305the current function... allowing it to be promoted to a simple SSA
306value instead of a memory location.</p>
307
308</div>
309
310<!-- _______________________________________________________________________ -->
311<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
312
313<div class="doc_text">
314
315<p>It is important to note that this document describes 'well formed'
316LLVM assembly language. There is a difference between what the parser
317accepts and what is considered 'well formed'. For example, the
318following instruction is syntactically okay, but not well formed:</p>
319
320<div class="doc_code">
321<pre>
322%x = <a href="#i_add">add</a> i32 1, %x
323</pre>
324</div>
325
326<p>...because the definition of <tt>%x</tt> does not dominate all of
327its uses. The LLVM infrastructure provides a verification pass that may
328be used to verify that an LLVM module is well formed. This pass is
329automatically run by the parser after parsing input assembly and by
330the optimizer before it outputs bitcode. The violations pointed out
331by the verifier pass indicate bugs in transformation passes or input to
332the parser.</p>
333</div>
334
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]335<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]336
337<!-- *********************************************************************** -->
338<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
339<!-- *********************************************************************** -->
340
341<div class="doc_text">
342
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]343 <p>LLVM identifiers come in two basic types: global and local. Global
344 identifiers (functions, global variables) begin with the @ character. Local
345 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]346 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
348<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]349 <li>Named values are represented as a string of characters with their prefix.
350 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
351 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]352 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]353 with quotes. Special characters may be escaped using "\xx" where xx is the
354 ASCII code for the character in hexadecimal. In this way, any character can
355 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]356
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]357 <li>Unnamed values are represented as an unsigned numeric value with their
358 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]359
360 <li>Constants, which are described in a <a href="#constants">section about
361 constants</a>, below.</li>
362</ol>
363
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]364<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]365don't need to worry about name clashes with reserved words, and the set of
366reserved words may be expanded in the future without penalty. Additionally,
367unnamed identifiers allow a compiler to quickly come up with a temporary
368variable without having to avoid symbol table conflicts.</p>
369
370<p>Reserved words in LLVM are very similar to reserved words in other
371languages. There are keywords for different opcodes
372('<tt><a href="#i_add">add</a></tt>',
373 '<tt><a href="#i_bitcast">bitcast</a></tt>',
374 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
375href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
376and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]377none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]378
379<p>Here is an example of LLVM code to multiply the integer variable
380'<tt>%X</tt>' by 8:</p>
381
382<p>The easy way:</p>
383
384<div class="doc_code">
385<pre>
386%result = <a href="#i_mul">mul</a> i32 %X, 8
387</pre>
388</div>
389
390<p>After strength reduction:</p>
391
392<div class="doc_code">
393<pre>
394%result = <a href="#i_shl">shl</a> i32 %X, i8 3
395</pre>
396</div>
397
398<p>And the hard way:</p>
399
400<div class="doc_code">
401<pre>
402<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
403<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
404%result = <a href="#i_add">add</a> i32 %1, %1
405</pre>
406</div>
407
408<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
409important lexical features of LLVM:</p>
410
411<ol>
412
413 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
414 line.</li>
415
416 <li>Unnamed temporaries are created when the result of a computation is not
417 assigned to a named value.</li>
418
419 <li>Unnamed temporaries are numbered sequentially</li>
420
421</ol>
422
423<p>...and it also shows a convention that we follow in this document. When
424demonstrating instructions, we will follow an instruction with a comment that
425defines the type and name of value produced. Comments are shown in italic
426text.</p>
427
428</div>
429
430<!-- *********************************************************************** -->
431<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
432<!-- *********************************************************************** -->
433
434<!-- ======================================================================= -->
435<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
436</div>
437
438<div class="doc_text">
439
440<p>LLVM programs are composed of "Module"s, each of which is a
441translation unit of the input programs. Each module consists of
442functions, global variables, and symbol table entries. Modules may be
443combined together with the LLVM linker, which merges function (and
444global variable) definitions, resolves forward declarations, and merges
445symbol table entries. Here is an example of the "hello world" module:</p>
446
447<div class="doc_code">
448<pre><i>; Declare the string constant as a global constant...</i>
449<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
450 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
451
452<i>; External declaration of the puts function</i>
453<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
454
455<i>; Definition of main function</i>
456define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]457 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]459 href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]460
461 <i>; Call puts function to write out the string to stdout...</i>
462 <a
463 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
464 <a
465 href="#i_ret">ret</a> i32 0<br>}<br>
466</pre>
467</div>
468
469<p>This example is made up of a <a href="#globalvars">global variable</a>
470named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
471function, and a <a href="#functionstructure">function definition</a>
472for "<tt>main</tt>".</p>
473
474<p>In general, a module is made up of a list of global values,
475where both functions and global variables are global values. Global values are
476represented by a pointer to a memory location (in this case, a pointer to an
477array of char, and a pointer to a function), and have one of the following <a
478href="#linkage">linkage types</a>.</p>
479
480</div>
481
482<!-- ======================================================================= -->
483<div class="doc_subsection">
484 <a name="linkage">Linkage Types</a>
485</div>
486
487<div class="doc_text">
488
489<p>
490All Global Variables and Functions have one of the following types of linkage:
491</p>
492
493<dl>
494
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]495 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
496
497 <dd>Global values with private linkage are only directly accessible by
498 objects in the current module. In particular, linking code into a module with
499 an private global value may cause the private to be renamed as necessary to
500 avoid collisions. Because the symbol is private to the module, all
501 references can be updated. This doesn't show up in any symbol table in the
502 object file.
503 </dd>
504
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]505 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]506
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]507 <dd> Similar to private, but the value shows as a local symbol (STB_LOCAL in
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]508 the case of ELF) in the object file. This corresponds to the notion of the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]509 '<tt>static</tt>' keyword in C.
510 </dd>
511
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]512 <dt><tt><b><a name="available_externally">available_externally</a></b></tt>:
513 </dt>
514
515 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
516 into the object file corresponding to the LLVM module. They exist to
517 allow inlining and other optimizations to take place given knowledge of the
518 definition of the global, which is known to be somewhere outside the module.
519 Globals with <tt>available_externally</tt> linkage are allowed to be discarded
520 at will, and are otherwise the same as <tt>linkonce_odr</tt>. This linkage
521 type is only allowed on definitions, not declarations.</dd>
522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]523 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
524
525 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
526 the same name when linkage occurs. This is typically used to implement
527 inline functions, templates, or other code which must be generated in each
528 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
529 allowed to be discarded.
530 </dd>
531
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]532 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
533
534 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
535 linkage, except that unreferenced <tt>common</tt> globals may not be
536 discarded. This is used for globals that may be emitted in multiple
537 translation units, but that are not guaranteed to be emitted into every
538 translation unit that uses them. One example of this is tentative
539 definitions in C, such as "<tt>int X;</tt>" at global scope.
540 </dd>
541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]542 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
543
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]544 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
545 that some targets may choose to emit different assembly sequences for them
546 for target-dependent reasons. This is used for globals that are declared
547 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]548 </dd>
549
550 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
551
552 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
553 pointer to array type. When two global variables with appending linkage are
554 linked together, the two global arrays are appended together. This is the
555 LLVM, typesafe, equivalent of having the system linker append together
556 "sections" with identical names when .o files are linked.
557 </dd>
558
559 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]560
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]561 <dd>The semantics of this linkage follow the ELF object file model: the
562 symbol is weak until linked, if not linked, the symbol becomes null instead
563 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564 </dd>
565
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]566 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]567 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]568 <dd>Some languages allow differing globals to be merged, such as two
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]569 functions with different semantics. Other languages, such as <tt>C++</tt>,
570 ensure that only equivalent globals are ever merged (the "one definition
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]571 rule" - "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Duncan Sandsb95df792009-03-11 20:14:15 +0000[diff] [blame]572 and <tt>weak_odr</tt> linkage types to indicate that the global will only
573 be merged with equivalent globals. These linkage types are otherwise the
574 same as their non-<tt>odr</tt> versions.
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]575 </dd>
576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
578
579 <dd>If none of the above identifiers are used, the global is externally
580 visible, meaning that it participates in linkage and can be used to resolve
581 external symbol references.
582 </dd>
583</dl>
584
585 <p>
586 The next two types of linkage are targeted for Microsoft Windows platform
587 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]588 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]589 </p>
590
591 <dl>
592 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
593
594 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
595 or variable via a global pointer to a pointer that is set up by the DLL
596 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]597 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]598 </dd>
599
600 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
601
602 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
603 pointer to a pointer in a DLL, so that it can be referenced with the
604 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]605 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]606 name.
607 </dd>
608
609</dl>
610
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]611<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]612variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
613variable and was linked with this one, one of the two would be renamed,
614preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
615external (i.e., lacking any linkage declarations), they are accessible
616outside of the current module.</p>
617<p>It is illegal for a function <i>declaration</i>
Duncan Sands565f65d2009-03-11 08:08:06 +0000[diff] [blame]618to have any linkage type other than "externally visible", <tt>dllimport</tt>
619or <tt>extern_weak</tt>.</p>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]620<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
621or <tt>weak_odr</tt> linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]622</div>
623
624<!-- ======================================================================= -->
625<div class="doc_subsection">
626 <a name="callingconv">Calling Conventions</a>
627</div>
628
629<div class="doc_text">
630
631<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
632and <a href="#i_invoke">invokes</a> can all have an optional calling convention
633specified for the call. The calling convention of any pair of dynamic
634caller/callee must match, or the behavior of the program is undefined. The
635following calling conventions are supported by LLVM, and more may be added in
636the future:</p>
637
638<dl>
639 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
640
641 <dd>This calling convention (the default if no other calling convention is
642 specified) matches the target C calling conventions. This calling convention
643 supports varargs function calls and tolerates some mismatch in the declared
644 prototype and implemented declaration of the function (as does normal C).
645 </dd>
646
647 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
648
649 <dd>This calling convention attempts to make calls as fast as possible
650 (e.g. by passing things in registers). This calling convention allows the
651 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]652 without having to conform to an externally specified ABI (Application Binary
653 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]654 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
655 supported. This calling convention does not support varargs and requires the
656 prototype of all callees to exactly match the prototype of the function
657 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]658 </dd>
659
660 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
661
662 <dd>This calling convention attempts to make code in the caller as efficient
663 as possible under the assumption that the call is not commonly executed. As
664 such, these calls often preserve all registers so that the call does not break
665 any live ranges in the caller side. This calling convention does not support
666 varargs and requires the prototype of all callees to exactly match the
667 prototype of the function definition.
668 </dd>
669
670 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
671
672 <dd>Any calling convention may be specified by number, allowing
673 target-specific calling conventions to be used. Target specific calling
674 conventions start at 64.
675 </dd>
676</dl>
677
678<p>More calling conventions can be added/defined on an as-needed basis, to
679support pascal conventions or any other well-known target-independent
680convention.</p>
681
682</div>
683
684<!-- ======================================================================= -->
685<div class="doc_subsection">
686 <a name="visibility">Visibility Styles</a>
687</div>
688
689<div class="doc_text">
690
691<p>
692All Global Variables and Functions have one of the following visibility styles:
693</p>
694
695<dl>
696 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
697
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]698 <dd>On targets that use the ELF object file format, default visibility means
699 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]700 modules and, in shared libraries, means that the declared entity may be
701 overridden. On Darwin, default visibility means that the declaration is
702 visible to other modules. Default visibility corresponds to "external
703 linkage" in the language.
704 </dd>
705
706 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
707
708 <dd>Two declarations of an object with hidden visibility refer to the same
709 object if they are in the same shared object. Usually, hidden visibility
710 indicates that the symbol will not be placed into the dynamic symbol table,
711 so no other module (executable or shared library) can reference it
712 directly.
713 </dd>
714
715 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
716
717 <dd>On ELF, protected visibility indicates that the symbol will be placed in
718 the dynamic symbol table, but that references within the defining module will
719 bind to the local symbol. That is, the symbol cannot be overridden by another
720 module.
721 </dd>
722</dl>
723
724</div>
725
726<!-- ======================================================================= -->
727<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]728 <a name="namedtypes">Named Types</a>
729</div>
730
731<div class="doc_text">
732
733<p>LLVM IR allows you to specify name aliases for certain types. This can make
734it easier to read the IR and make the IR more condensed (particularly when
735recursive types are involved). An example of a name specification is:
736</p>
737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
744<p>You may give a name to any <a href="#typesystem">type</a> except "<a
745href="t_void">void</a>". Type name aliases may be used anywhere a type is
746expected with the syntax "%mytype".</p>
747
748<p>Note that type names are aliases for the structural type that they indicate,
749and that you can therefore specify multiple names for the same type. This often
750leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
751structural typing, the name is not part of the type. When printing out LLVM IR,
752the printer will pick <em>one name</em> to render all types of a particular
753shape. This means that if you have code where two different source types end up
754having the same LLVM type, that the dumper will sometimes print the "wrong" or
755unexpected type. This is an important design point and isn't going to
756change.</p>
757
758</div>
759
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]760<!-- ======================================================================= -->
761<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
767<p>Global variables define regions of memory allocated at compilation time
768instead of run-time. Global variables may optionally be initialized, may have
769an explicit section to be placed in, and may have an optional explicit alignment
770specified. A variable may be defined as "thread_local", which means that it
771will not be shared by threads (each thread will have a separated copy of the
772variable). A variable may be defined as a global "constant," which indicates
773that the contents of the variable will <b>never</b> be modified (enabling better
774optimization, allowing the global data to be placed in the read-only section of
775an executable, etc). Note that variables that need runtime initialization
776cannot be marked "constant" as there is a store to the variable.</p>
777
778<p>
779LLVM explicitly allows <em>declarations</em> of global variables to be marked
780constant, even if the final definition of the global is not. This capability
781can be used to enable slightly better optimization of the program, but requires
782the language definition to guarantee that optimizations based on the
783'constantness' are valid for the translation units that do not include the
784definition.
785</p>
786
787<p>As SSA values, global variables define pointer values that are in
788scope (i.e. they dominate) all basic blocks in the program. Global
789variables always define a pointer to their "content" type because they
790describe a region of memory, and all memory objects in LLVM are
791accessed through pointers.</p>
792
Chris Lattner990e7652009-07-18 21:47:15 +0000[diff] [blame^]793<p>A global variable may be declared to reside in a target-specific numbered
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]794address space. For targets that support them, address spaces may affect how
795optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]796the variable. The default address space is zero. The address space qualifier
797must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]799<p>LLVM allows an explicit section to be specified for globals. If the target
800supports it, it will emit globals to the section specified.</p>
801
802<p>An explicit alignment may be specified for a global. If not present, or if
803the alignment is set to zero, the alignment of the global is set by the target
804to whatever it feels convenient. If an explicit alignment is specified, the
805global is forced to have at least that much alignment. All alignments must be
806a power of 2.</p>
807
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]808<p>For example, the following defines a global in a numbered address space with
809an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]810
811<div class="doc_code">
812<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]813@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814</pre>
815</div>
816
817</div>
818
819
820<!-- ======================================================================= -->
821<div class="doc_subsection">
822 <a name="functionstructure">Functions</a>
823</div>
824
825<div class="doc_text">
826
827<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
828an optional <a href="#linkage">linkage type</a>, an optional
829<a href="#visibility">visibility style</a>, an optional
830<a href="#callingconv">calling convention</a>, a return type, an optional
831<a href="#paramattrs">parameter attribute</a> for the return type, a function
832name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]833<a href="#paramattrs">parameter attributes</a>), optional
834<a href="#fnattrs">function attributes</a>, an optional section,
835an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]836an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]837
838LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
839optional <a href="#linkage">linkage type</a>, an optional
840<a href="#visibility">visibility style</a>, an optional
841<a href="#callingconv">calling convention</a>, a return type, an optional
842<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]843name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]844<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]845
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]846<p>A function definition contains a list of basic blocks, forming the CFG
847(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]848the function. Each basic block may optionally start with a label (giving the
849basic block a symbol table entry), contains a list of instructions, and ends
850with a <a href="#terminators">terminator</a> instruction (such as a branch or
851function return).</p>
852
853<p>The first basic block in a function is special in two ways: it is immediately
854executed on entrance to the function, and it is not allowed to have predecessor
855basic blocks (i.e. there can not be any branches to the entry block of a
856function). Because the block can have no predecessors, it also cannot have any
857<a href="#i_phi">PHI nodes</a>.</p>
858
859<p>LLVM allows an explicit section to be specified for functions. If the target
860supports it, it will emit functions to the section specified.</p>
861
862<p>An explicit alignment may be specified for a function. If not present, or if
863the alignment is set to zero, the alignment of the function is set by the target
864to whatever it feels convenient. If an explicit alignment is specified, the
865function is forced to have at least that much alignment. All alignments must be
866a power of 2.</p>
867
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]868 <h5>Syntax:</h5>
869
870<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]871<tt>
872define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
873 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
874 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
875 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
876 [<a href="#gc">gc</a>] { ... }
877</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]878</div>
879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]880</div>
881
882
883<!-- ======================================================================= -->
884<div class="doc_subsection">
885 <a name="aliasstructure">Aliases</a>
886</div>
887<div class="doc_text">
888 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]889 function, global variable, another alias or bitcast of global value). Aliases
890 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]891 optional <a href="#visibility">visibility style</a>.</p>
892
893 <h5>Syntax:</h5>
894
895<div class="doc_code">
896<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]897@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]898</pre>
899</div>
900
901</div>
902
903
904
905<!-- ======================================================================= -->
906<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
907<div class="doc_text">
908 <p>The return type and each parameter of a function type may have a set of
909 <i>parameter attributes</i> associated with them. Parameter attributes are
910 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]911 a function. Parameter attributes are considered to be part of the function,
912 not of the function type, so functions with different parameter attributes
913 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]914
915 <p>Parameter attributes are simple keywords that follow the type specified. If
916 multiple parameter attributes are needed, they are space separated. For
917 example:</p>
918
919<div class="doc_code">
920<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]921declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]922declare i32 @atoi(i8 zeroext)
923declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]924</pre>
925</div>
926
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]927 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
928 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]929
930 <p>Currently, only the following parameter attributes are defined:</p>
931 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]932 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]933 <dd>This indicates to the code generator that the parameter or return value
934 should be zero-extended to a 32-bit value by the caller (for a parameter)
935 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]936
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]937 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]938 <dd>This indicates to the code generator that the parameter or return value
939 should be sign-extended to a 32-bit value by the caller (for a parameter)
940 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]942 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]943 <dd>This indicates that this parameter or return value should be treated
944 in a special target-dependent fashion during while emitting code for a
945 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]946 to memory, though some targets use it to distinguish between two different
947 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]948
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]949 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]950 <dd>This indicates that the pointer parameter should really be passed by
951 value to the function. The attribute implies that a hidden copy of the
952 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]953 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]954 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]955 value, but is also valid on pointers to scalars. The copy is considered to
956 belong to the caller not the callee (for example,
957 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]958 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnere39c5bf2009-02-05 05:42:28 +0000[diff] [blame]959 values. The byval attribute also supports specifying an alignment with the
960 align attribute. This has a target-specific effect on the code generator
961 that usually indicates a desired alignment for the synthesized stack
962 slot.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]964 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]965 <dd>This indicates that the pointer parameter specifies the address of a
966 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]967 This pointer must be guaranteed by the caller to be valid: loads and stores
968 to the structure may be assumed by the callee to not to trap. This may only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]969 be applied to the first parameter. This is not a valid attribute for
970 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]972 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]973 <dd>This indicates that the pointer does not alias any global or any other
974 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]975 case. On a function return value, <tt>noalias</tt> additionally indicates
976 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]977 caller. For further details, please see the discussion of the NoAlias
978 response in
979 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
980 analysis</a>.</dd>
981
982 <dt><tt>nocapture</tt></dt>
983 <dd>This indicates that the callee does not make any copies of the pointer
984 that outlive the callee itself. This is not a valid attribute for return
985 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]986
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]987 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]988 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]989 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
990 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]991 </dl>
992
993</div>
994
995<!-- ======================================================================= -->
996<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]997 <a name="gc">Garbage Collector Names</a>
998</div>
999
1000<div class="doc_text">
1001<p>Each function may specify a garbage collector name, which is simply a
1002string.</p>
1003
1004<div class="doc_code"><pre
1005>define void @f() gc "name" { ...</pre></div>
1006
1007<p>The compiler declares the supported values of <i>name</i>. Specifying a
1008collector which will cause the compiler to alter its output in order to support
1009the named garbage collection algorithm.</p>
1010</div>
1011
1012<!-- ======================================================================= -->
1013<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1014 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1015</div>
1016
1017<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1018
1019<p>Function attributes are set to communicate additional information about
1020 a function. Function attributes are considered to be part of the function,
1021 not of the function type, so functions with different parameter attributes
1022 can have the same function type.</p>
1023
1024 <p>Function attributes are simple keywords that follow the type specified. If
1025 multiple attributes are needed, they are space separated. For
1026 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1027
1028<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1029<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1030define void @f() noinline { ... }
1031define void @f() alwaysinline { ... }
1032define void @f() alwaysinline optsize { ... }
1033define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1034</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1035</div>
1036
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1037<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1038<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1039<dd>This attribute indicates that the inliner should attempt to inline this
1040function into callers whenever possible, ignoring any active inlining size
1041threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1042
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1043<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1044<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1045in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1046<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1047
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1048<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1049<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1050make choices that keep the code size of this function low, and otherwise do
1051optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1052
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1053<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1054<dd>This function attribute indicates that the function never returns normally.
1055This produces undefined behavior at runtime if the function ever does
1056dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1057
1058<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1059<dd>This function attribute indicates that the function never returns with an
1060unwind or exceptional control flow. If the function does unwind, its runtime
1061behavior is undefined.</dd>
1062
1063<dt><tt>readnone</tt></dt>
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1064<dd>This attribute indicates that the function computes its result (or decides to
1065unwind an exception) based strictly on its arguments, without dereferencing any
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1066pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1067registers, etc) visible to caller functions. It does not write through any
1068pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1069never changes any state visible to callers. This means that it cannot unwind
1070exceptions by calling the <tt>C++</tt> exception throwing methods, but could
1071use the <tt>unwind</tt> instruction.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1072
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1073<dt><tt><a name="readonly">readonly</a></tt></dt>
1074<dd>This attribute indicates that the function does not write through any
1075pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1076or otherwise modify any state (e.g. memory, control registers, etc) visible to
1077caller functions. It may dereference pointer arguments and read state that may
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1078be set in the caller. A readonly function always returns the same value (or
1079unwinds an exception identically) when called with the same set of arguments
1080and global state. It cannot unwind an exception by calling the <tt>C++</tt>
1081exception throwing methods, but may use the <tt>unwind</tt> instruction.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1082
1083<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1084<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1085protector. It is in the form of a "canary"&mdash;a random value placed on the
1086stack before the local variables that's checked upon return from the function to
1087see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1088needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1089
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1090<br><br>If a function that has an <tt>ssp</tt> attribute is inlined into a function
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1091that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1092have an <tt>ssp</tt> attribute.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1093
1094<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1095<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1096stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1097function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1098
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1099If a function that has an <tt>sspreq</tt> attribute is inlined into a
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1100function that doesn't have an <tt>sspreq</tt> attribute or which has
1101an <tt>ssp</tt> attribute, then the resulting function will have
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1102an <tt>sspreq</tt> attribute.</dd>
1103
1104<dt><tt>noredzone</tt></dt>
Dan Gohman06c9b732009-06-15 17:37:09 +0000[diff] [blame]1105<dd>This attribute indicates that the code generator should not use a
Dan Gohmanf958d5c2009-06-15 21:18:01 +0000[diff] [blame]1106red zone, even if the target-specific ABI normally permits it.
Dan Gohman06c9b732009-06-15 17:37:09 +0000[diff] [blame]1107</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1108
1109<dt><tt>noimplicitfloat</tt></dt>
1110<dd>This attributes disables implicit floating point instructions.</dd>
1111
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1112<dt><tt>naked</tt></dt>
Chris Lattnerc529b882009-07-17 21:14:28 +0000[diff] [blame]1113<dd>This attribute disables prologue / epilogue emission for the function.
1114This can have very system-specific consequences.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1115
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1116</dl>
1117
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1118</div>
1119
1120<!-- ======================================================================= -->
1121<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1122 <a name="moduleasm">Module-Level Inline Assembly</a>
1123</div>
1124
1125<div class="doc_text">
1126<p>
1127Modules may contain "module-level inline asm" blocks, which corresponds to the
1128GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1129LLVM and treated as a single unit, but may be separated in the .ll file if
1130desired. The syntax is very simple:
1131</p>
1132
1133<div class="doc_code">
1134<pre>
1135module asm "inline asm code goes here"
1136module asm "more can go here"
1137</pre>
1138</div>
1139
1140<p>The strings can contain any character by escaping non-printable characters.
1141 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1142 for the number.
1143</p>
1144
1145<p>
1146 The inline asm code is simply printed to the machine code .s file when
1147 assembly code is generated.
1148</p>
1149</div>
1150
1151<!-- ======================================================================= -->
1152<div class="doc_subsection">
1153 <a name="datalayout">Data Layout</a>
1154</div>
1155
1156<div class="doc_text">
1157<p>A module may specify a target specific data layout string that specifies how
1158data is to be laid out in memory. The syntax for the data layout is simply:</p>
1159<pre> target datalayout = "<i>layout specification</i>"</pre>
1160<p>The <i>layout specification</i> consists of a list of specifications
1161separated by the minus sign character ('-'). Each specification starts with a
1162letter and may include other information after the letter to define some
1163aspect of the data layout. The specifications accepted are as follows: </p>
1164<dl>
1165 <dt><tt>E</tt></dt>
1166 <dd>Specifies that the target lays out data in big-endian form. That is, the
1167 bits with the most significance have the lowest address location.</dd>
1168 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1169 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1170 the bits with the least significance have the lowest address location.</dd>
1171 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1172 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1173 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1174 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1175 too.</dd>
1176 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1177 <dd>This specifies the alignment for an integer type of a given bit
1178 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1179 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1180 <dd>This specifies the alignment for a vector type of a given bit
1181 <i>size</i>.</dd>
1182 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1183 <dd>This specifies the alignment for a floating point type of a given bit
1184 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1185 (double).</dd>
1186 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1187 <dd>This specifies the alignment for an aggregate type of a given bit
1188 <i>size</i>.</dd>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1189 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1190 <dd>This specifies the alignment for a stack object of a given bit
1191 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1192</dl>
1193<p>When constructing the data layout for a given target, LLVM starts with a
1194default set of specifications which are then (possibly) overriden by the
1195specifications in the <tt>datalayout</tt> keyword. The default specifications
1196are given in this list:</p>
1197<ul>
1198 <li><tt>E</tt> - big endian</li>
1199 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1200 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1201 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1202 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1203 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1204 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1205 alignment of 64-bits</li>
1206 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1207 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1208 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1209 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1210 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1211 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1212</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1213<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1214following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1215<ol>
1216 <li>If the type sought is an exact match for one of the specifications, that
1217 specification is used.</li>
1218 <li>If no match is found, and the type sought is an integer type, then the
1219 smallest integer type that is larger than the bitwidth of the sought type is
1220 used. If none of the specifications are larger than the bitwidth then the the
1221 largest integer type is used. For example, given the default specifications
1222 above, the i7 type will use the alignment of i8 (next largest) while both
1223 i65 and i256 will use the alignment of i64 (largest specified).</li>
1224 <li>If no match is found, and the type sought is a vector type, then the
1225 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1226 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1227 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1228</ol>
1229</div>
1230
1231<!-- *********************************************************************** -->
1232<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1233<!-- *********************************************************************** -->
1234
1235<div class="doc_text">
1236
1237<p>The LLVM type system is one of the most important features of the
1238intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1239optimizations to be performed on the intermediate representation directly,
1240without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1241extra analyses on the side before the transformation. A strong type
1242system makes it easier to read the generated code and enables novel
1243analyses and transformations that are not feasible to perform on normal
1244three address code representations.</p>
1245
1246</div>
1247
1248<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1249<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1250Classifications</a> </div>
1251<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1252<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1253classifications:</p>
1254
1255<table border="1" cellspacing="0" cellpadding="4">
1256 <tbody>
1257 <tr><th>Classification</th><th>Types</th></tr>
1258 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1259 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1260 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1261 </tr>
1262 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1263 <td><a href="#t_floating">floating point</a></td>
1264 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1265 </tr>
1266 <tr>
1267 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1268 <td><a href="#t_integer">integer</a>,
1269 <a href="#t_floating">floating point</a>,
1270 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1271 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1272 <a href="#t_struct">structure</a>,
1273 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1274 <a href="#t_label">label</a>,
1275 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1276 </td>
1277 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1278 <tr>
1279 <td><a href="#t_primitive">primitive</a></td>
1280 <td><a href="#t_label">label</a>,
1281 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1282 <a href="#t_floating">floating point</a>,
1283 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1284 </tr>
1285 <tr>
1286 <td><a href="#t_derived">derived</a></td>
1287 <td><a href="#t_integer">integer</a>,
1288 <a href="#t_array">array</a>,
1289 <a href="#t_function">function</a>,
1290 <a href="#t_pointer">pointer</a>,
1291 <a href="#t_struct">structure</a>,
1292 <a href="#t_pstruct">packed structure</a>,
1293 <a href="#t_vector">vector</a>,
1294 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1295 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1296 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1297 </tbody>
1298</table>
1299
1300<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1301most important. Values of these types are the only ones which can be
1302produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1303instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1304</div>
1305
1306<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1307<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1308
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1309<div class="doc_text">
1310<p>The primitive types are the fundamental building blocks of the LLVM
1311system.</p>
1312
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1313</div>
1314
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1315<!-- _______________________________________________________________________ -->
1316<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1317
1318<div class="doc_text">
1319 <table>
1320 <tbody>
1321 <tr><th>Type</th><th>Description</th></tr>
1322 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1323 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1324 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1325 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1326 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1327 </tbody>
1328 </table>
1329</div>
1330
1331<!-- _______________________________________________________________________ -->
1332<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1333
1334<div class="doc_text">
1335<h5>Overview:</h5>
1336<p>The void type does not represent any value and has no size.</p>
1337
1338<h5>Syntax:</h5>
1339
1340<pre>
1341 void
1342</pre>
1343</div>
1344
1345<!-- _______________________________________________________________________ -->
1346<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1347
1348<div class="doc_text">
1349<h5>Overview:</h5>
1350<p>The label type represents code labels.</p>
1351
1352<h5>Syntax:</h5>
1353
1354<pre>
1355 label
1356</pre>
1357</div>
1358
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1359<!-- _______________________________________________________________________ -->
1360<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1361
1362<div class="doc_text">
1363<h5>Overview:</h5>
1364<p>The metadata type represents embedded metadata. The only derived type that
1365may contain metadata is <tt>metadata*</tt> or a function type that returns or
1366takes metadata typed parameters, but not pointer to metadata types.</p>
1367
1368<h5>Syntax:</h5>
1369
1370<pre>
1371 metadata
1372</pre>
1373</div>
1374
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1375
1376<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1377<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1378
1379<div class="doc_text">
1380
1381<p>The real power in LLVM comes from the derived types in the system.
1382This is what allows a programmer to represent arrays, functions,
1383pointers, and other useful types. Note that these derived types may be
1384recursive: For example, it is possible to have a two dimensional array.</p>
1385
1386</div>
1387
1388<!-- _______________________________________________________________________ -->
1389<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1390
1391<div class="doc_text">
1392
1393<h5>Overview:</h5>
1394<p>The integer type is a very simple derived type that simply specifies an
1395arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13962^23-1 (about 8 million) can be specified.</p>
1397
1398<h5>Syntax:</h5>
1399
1400<pre>
1401 iN
1402</pre>
1403
1404<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1405value.</p>
1406
1407<h5>Examples:</h5>
1408<table class="layout">
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1409 <tr class="layout">
1410 <td class="left"><tt>i1</tt></td>
1411 <td class="left">a single-bit integer.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1412 </tr>
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1413 <tr class="layout">
1414 <td class="left"><tt>i32</tt></td>
1415 <td class="left">a 32-bit integer.</td>
1416 </tr>
1417 <tr class="layout">
1418 <td class="left"><tt>i1942652</tt></td>
1419 <td class="left">a really big integer of over 1 million bits.</td>
1420 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1421</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1422
1423<p>Note that the code generator does not yet support large integer types
1424to be used as function return types. The specific limit on how large a
1425return type the code generator can currently handle is target-dependent;
1426currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1427targets.</p>
1428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1429</div>
1430
1431<!-- _______________________________________________________________________ -->
1432<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1433
1434<div class="doc_text">
1435
1436<h5>Overview:</h5>
1437
1438<p>The array type is a very simple derived type that arranges elements
1439sequentially in memory. The array type requires a size (number of
1440elements) and an underlying data type.</p>
1441
1442<h5>Syntax:</h5>
1443
1444<pre>
1445 [&lt;# elements&gt; x &lt;elementtype&gt;]
1446</pre>
1447
1448<p>The number of elements is a constant integer value; elementtype may
1449be any type with a size.</p>
1450
1451<h5>Examples:</h5>
1452<table class="layout">
1453 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1454 <td class="left"><tt>[40 x i32]</tt></td>
1455 <td class="left">Array of 40 32-bit integer values.</td>
1456 </tr>
1457 <tr class="layout">
1458 <td class="left"><tt>[41 x i32]</tt></td>
1459 <td class="left">Array of 41 32-bit integer values.</td>
1460 </tr>
1461 <tr class="layout">
1462 <td class="left"><tt>[4 x i8]</tt></td>
1463 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1464 </tr>
1465</table>
1466<p>Here are some examples of multidimensional arrays:</p>
1467<table class="layout">
1468 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1469 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1470 <td class="left">3x4 array of 32-bit integer values.</td>
1471 </tr>
1472 <tr class="layout">
1473 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1474 <td class="left">12x10 array of single precision floating point values.</td>
1475 </tr>
1476 <tr class="layout">
1477 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1478 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1479 </tr>
1480</table>
1481
1482<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1483length array. Normally, accesses past the end of an array are undefined in
1484LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1485As a special case, however, zero length arrays are recognized to be variable
1486length. This allows implementation of 'pascal style arrays' with the LLVM
1487type "{ i32, [0 x float]}", for example.</p>
1488
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1489<p>Note that the code generator does not yet support large aggregate types
1490to be used as function return types. The specific limit on how large an
1491aggregate return type the code generator can currently handle is
1492target-dependent, and also dependent on the aggregate element types.</p>
1493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1494</div>
1495
1496<!-- _______________________________________________________________________ -->
1497<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1498<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1499
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1500<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1502<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1503consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1504return type of a function type is a scalar type, a void type, or a struct type.
Devang Pateld5404c02008-03-24 20:52:42 +0000[diff] [blame]1505If the return type is a struct type then all struct elements must be of first
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1506class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1508<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1509
1510<pre>
1511 &lt;returntype list&gt; (&lt;parameter list&gt;)
1512</pre>
1513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1514<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1515specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1516which indicates that the function takes a variable number of arguments.
1517Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1518 href="#int_varargs">variable argument handling intrinsic</a> functions.
1519'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1520<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1522<h5>Examples:</h5>
1523<table class="layout">
1524 <tr class="layout">
1525 <td class="left"><tt>i32 (i32)</tt></td>
1526 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1527 </td>
1528 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1529 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1530 </tt></td>
1531 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1532 an <tt>i16</tt> that should be sign extended and a
1533 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1534 <tt>float</tt>.
1535 </td>
1536 </tr><tr class="layout">
1537 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1538 <td class="left">A vararg function that takes at least one
1539 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1540 which returns an integer. This is the signature for <tt>printf</tt> in
1541 LLVM.
1542 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1543 </tr><tr class="layout">
1544 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1545 <td class="left">A function taking an <tt>i32</tt>, returning two
1546 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1547 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1548 </tr>
1549</table>
1550
1551</div>
1552<!-- _______________________________________________________________________ -->
1553<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1554<div class="doc_text">
1555<h5>Overview:</h5>
1556<p>The structure type is used to represent a collection of data members
1557together in memory. The packing of the field types is defined to match
1558the ABI of the underlying processor. The elements of a structure may
1559be any type that has a size.</p>
1560<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1561and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1562field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1563instruction.</p>
1564<h5>Syntax:</h5>
1565<pre> { &lt;type list&gt; }<br></pre>
1566<h5>Examples:</h5>
1567<table class="layout">
1568 <tr class="layout">
1569 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1570 <td class="left">A triple of three <tt>i32</tt> values</td>
1571 </tr><tr class="layout">
1572 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1573 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1574 second element is a <a href="#t_pointer">pointer</a> to a
1575 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1576 an <tt>i32</tt>.</td>
1577 </tr>
1578</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1579
1580<p>Note that the code generator does not yet support large aggregate types
1581to be used as function return types. The specific limit on how large an
1582aggregate return type the code generator can currently handle is
1583target-dependent, and also dependent on the aggregate element types.</p>
1584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1585</div>
1586
1587<!-- _______________________________________________________________________ -->
1588<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1589</div>
1590<div class="doc_text">
1591<h5>Overview:</h5>
1592<p>The packed structure type is used to represent a collection of data members
1593together in memory. There is no padding between fields. Further, the alignment
1594of a packed structure is 1 byte. The elements of a packed structure may
1595be any type that has a size.</p>
1596<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1597and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1598field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1599instruction.</p>
1600<h5>Syntax:</h5>
1601<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1602<h5>Examples:</h5>
1603<table class="layout">
1604 <tr class="layout">
1605 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1606 <td class="left">A triple of three <tt>i32</tt> values</td>
1607 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1608 <td class="left">
1609<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1610 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1611 second element is a <a href="#t_pointer">pointer</a> to a
1612 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1613 an <tt>i32</tt>.</td>
1614 </tr>
1615</table>
1616</div>
1617
1618<!-- _______________________________________________________________________ -->
1619<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1620<div class="doc_text">
1621<h5>Overview:</h5>
1622<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1623reference to another object, which must live in memory. Pointer types may have
1624an optional address space attribute defining the target-specific numbered
1625address space where the pointed-to object resides. The default address space is
1626zero.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1627
1628<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does
Chris Lattner0d879e02009-02-08 22:21:28 +0000[diff] [blame]1629it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1631<h5>Syntax:</h5>
1632<pre> &lt;type&gt; *<br></pre>
1633<h5>Examples:</h5>
1634<table class="layout">
1635 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1636 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1637 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1638 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1639 </tr>
1640 <tr class="layout">
1641 <td class="left"><tt>i32 (i32 *) *</tt></td>
1642 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1643 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1644 <tt>i32</tt>.</td>
1645 </tr>
1646 <tr class="layout">
1647 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1648 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1649 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1650 </tr>
1651</table>
1652</div>
1653
1654<!-- _______________________________________________________________________ -->
1655<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1656<div class="doc_text">
1657
1658<h5>Overview:</h5>
1659
1660<p>A vector type is a simple derived type that represents a vector
1661of elements. Vector types are used when multiple primitive data
1662are operated in parallel using a single instruction (SIMD).
1663A vector type requires a size (number of
1664elements) and an underlying primitive data type. Vectors must have a power
1665of two length (1, 2, 4, 8, 16 ...). Vector types are
1666considered <a href="#t_firstclass">first class</a>.</p>
1667
1668<h5>Syntax:</h5>
1669
1670<pre>
1671 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1672</pre>
1673
1674<p>The number of elements is a constant integer value; elementtype may
1675be any integer or floating point type.</p>
1676
1677<h5>Examples:</h5>
1678
1679<table class="layout">
1680 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1681 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1682 <td class="left">Vector of 4 32-bit integer values.</td>
1683 </tr>
1684 <tr class="layout">
1685 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1686 <td class="left">Vector of 8 32-bit floating-point values.</td>
1687 </tr>
1688 <tr class="layout">
1689 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1690 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1691 </tr>
1692</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1693
1694<p>Note that the code generator does not yet support large vector types
1695to be used as function return types. The specific limit on how large a
1696vector return type codegen can currently handle is target-dependent;
1697currently it's often a few times longer than a hardware vector register.</p>
1698
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1699</div>
1700
1701<!-- _______________________________________________________________________ -->
1702<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1703<div class="doc_text">
1704
1705<h5>Overview:</h5>
1706
1707<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1708corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1709In LLVM, opaque types can eventually be resolved to any type (not just a
1710structure type).</p>
1711
1712<h5>Syntax:</h5>
1713
1714<pre>
1715 opaque
1716</pre>
1717
1718<h5>Examples:</h5>
1719
1720<table class="layout">
1721 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1722 <td class="left"><tt>opaque</tt></td>
1723 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1724 </tr>
1725</table>
1726</div>
1727
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1728<!-- ======================================================================= -->
1729<div class="doc_subsection">
1730 <a name="t_uprefs">Type Up-references</a>
1731</div>
1732
1733<div class="doc_text">
1734<h5>Overview:</h5>
1735<p>
1736An "up reference" allows you to refer to a lexically enclosing type without
1737requiring it to have a name. For instance, a structure declaration may contain a
1738pointer to any of the types it is lexically a member of. Example of up
1739references (with their equivalent as named type declarations) include:</p>
1740
1741<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1742 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1743 { \2 }* %y = type { %y }*
1744 \1* %z = type %z*
1745</pre>
1746
1747<p>
1748An up reference is needed by the asmprinter for printing out cyclic types when
1749there is no declared name for a type in the cycle. Because the asmprinter does
1750not want to print out an infinite type string, it needs a syntax to handle
1751recursive types that have no names (all names are optional in llvm IR).
1752</p>
1753
1754<h5>Syntax:</h5>
1755<pre>
1756 \&lt;level&gt;
1757</pre>
1758
1759<p>
1760The level is the count of the lexical type that is being referred to.
1761</p>
1762
1763<h5>Examples:</h5>
1764
1765<table class="layout">
1766 <tr class="layout">
1767 <td class="left"><tt>\1*</tt></td>
1768 <td class="left">Self-referential pointer.</td>
1769 </tr>
1770 <tr class="layout">
1771 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1772 <td class="left">Recursive structure where the upref refers to the out-most
1773 structure.</td>
1774 </tr>
1775</table>
1776</div>
1777
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1778
1779<!-- *********************************************************************** -->
1780<div class="doc_section"> <a name="constants">Constants</a> </div>
1781<!-- *********************************************************************** -->
1782
1783<div class="doc_text">
1784
1785<p>LLVM has several different basic types of constants. This section describes
1786them all and their syntax.</p>
1787
1788</div>
1789
1790<!-- ======================================================================= -->
1791<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1792
1793<div class="doc_text">
1794
1795<dl>
1796 <dt><b>Boolean constants</b></dt>
1797
1798 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1799 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1800 </dd>
1801
1802 <dt><b>Integer constants</b></dt>
1803
1804 <dd>Standard integers (such as '4') are constants of the <a
1805 href="#t_integer">integer</a> type. Negative numbers may be used with
1806 integer types.
1807 </dd>
1808
1809 <dt><b>Floating point constants</b></dt>
1810
1811 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1812 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1813 notation (see below). The assembler requires the exact decimal value of
1814 a floating-point constant. For example, the assembler accepts 1.25 but
1815 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1816 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1817
1818 <dt><b>Null pointer constants</b></dt>
1819
1820 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1821 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1822
1823</dl>
1824
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1825<p>The one non-intuitive notation for constants is the hexadecimal form
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1826of floating point constants. For example, the form '<tt>double
18270x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
18284.5e+15</tt>'. The only time hexadecimal floating point constants are required
1829(and the only time that they are generated by the disassembler) is when a
1830floating point constant must be emitted but it cannot be represented as a
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1831decimal floating point number in a reasonable number of digits. For example,
1832NaN's, infinities, and other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1833special values are represented in their IEEE hexadecimal format so that
1834assembly and disassembly do not cause any bits to change in the constants.</p>
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1835<p>When using the hexadecimal form, constants of types float and double are
1836represented using the 16-digit form shown above (which matches the IEEE754
1837representation for double); float values must, however, be exactly representable
1838as IEE754 single precision.
1839Hexadecimal format is always used for long
1840double, and there are three forms of long double. The 80-bit
1841format used by x86 is represented as <tt>0xK</tt>
1842followed by 20 hexadecimal digits.
1843The 128-bit format used by PowerPC (two adjacent doubles) is represented
1844by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
1845format is represented
1846by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
1847target uses this format. Long doubles will only work if they match
1848the long double format on your target. All hexadecimal formats are big-endian
1849(sign bit at the left).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1850</div>
1851
1852<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1853<div class="doc_subsection">
1854<a name="aggregateconstants"> <!-- old anchor -->
1855<a name="complexconstants">Complex Constants</a></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1856</div>
1857
1858<div class="doc_text">
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1859<p>Complex constants are a (potentially recursive) combination of simple
1860constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1861
1862<dl>
1863 <dt><b>Structure constants</b></dt>
1864
1865 <dd>Structure constants are represented with notation similar to structure
1866 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1867 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1868 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1869 must have <a href="#t_struct">structure type</a>, and the number and
1870 types of elements must match those specified by the type.
1871 </dd>
1872
1873 <dt><b>Array constants</b></dt>
1874
1875 <dd>Array constants are represented with notation similar to array type
1876 definitions (a comma separated list of elements, surrounded by square brackets
1877 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1878 constants must have <a href="#t_array">array type</a>, and the number and
1879 types of elements must match those specified by the type.
1880 </dd>
1881
1882 <dt><b>Vector constants</b></dt>
1883
1884 <dd>Vector constants are represented with notation similar to vector type
1885 definitions (a comma separated list of elements, surrounded by
1886 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1887 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1888 href="#t_vector">vector type</a>, and the number and types of elements must
1889 match those specified by the type.
1890 </dd>
1891
1892 <dt><b>Zero initialization</b></dt>
1893
1894 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1895 value to zero of <em>any</em> type, including scalar and aggregate types.
1896 This is often used to avoid having to print large zero initializers (e.g. for
1897 large arrays) and is always exactly equivalent to using explicit zero
1898 initializers.
1899 </dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1900
1901 <dt><b>Metadata node</b></dt>
1902
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1903 <dd>A metadata node is a structure-like constant with
1904 <a href="#t_metadata">metadata type</a>. For example:
1905 "<tt>metadata !{ i32 0, metadata !"test" }</tt>". Unlike other constants
1906 that are meant to be interpreted as part of the instruction stream, metadata
1907 is a place to attach additional information such as debug info.
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1908 </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1909</dl>
1910
1911</div>
1912
1913<!-- ======================================================================= -->
1914<div class="doc_subsection">
1915 <a name="globalconstants">Global Variable and Function Addresses</a>
1916</div>
1917
1918<div class="doc_text">
1919
1920<p>The addresses of <a href="#globalvars">global variables</a> and <a
1921href="#functionstructure">functions</a> are always implicitly valid (link-time)
1922constants. These constants are explicitly referenced when the <a
1923href="#identifiers">identifier for the global</a> is used and always have <a
1924href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1925file:</p>
1926
1927<div class="doc_code">
1928<pre>
1929@X = global i32 17
1930@Y = global i32 42
1931@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1932</pre>
1933</div>
1934
1935</div>
1936
1937<!-- ======================================================================= -->
1938<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1939<div class="doc_text">
1940 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1941 no specific value. Undefined values may be of any type and be used anywhere
1942 a constant is permitted.</p>
1943
1944 <p>Undefined values indicate to the compiler that the program is well defined
1945 no matter what value is used, giving the compiler more freedom to optimize.
1946 </p>
1947</div>
1948
1949<!-- ======================================================================= -->
1950<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1951</div>
1952
1953<div class="doc_text">
1954
1955<p>Constant expressions are used to allow expressions involving other constants
1956to be used as constants. Constant expressions may be of any <a
1957href="#t_firstclass">first class</a> type and may involve any LLVM operation
1958that does not have side effects (e.g. load and call are not supported). The
1959following is the syntax for constant expressions:</p>
1960
1961<dl>
1962 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1963 <dd>Truncate a constant to another type. The bit size of CST must be larger
1964 than the bit size of TYPE. Both types must be integers.</dd>
1965
1966 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1967 <dd>Zero extend a constant to another type. The bit size of CST must be
1968 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1969
1970 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1971 <dd>Sign extend a constant to another type. The bit size of CST must be
1972 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1973
1974 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1975 <dd>Truncate a floating point constant to another floating point type. The
1976 size of CST must be larger than the size of TYPE. Both types must be
1977 floating point.</dd>
1978
1979 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1980 <dd>Floating point extend a constant to another type. The size of CST must be
1981 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1982
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1983 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1984 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1985 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1986 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1987 of the same number of elements. If the value won't fit in the integer type,
1988 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1989
1990 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1991 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1992 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1993 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1994 of the same number of elements. If the value won't fit in the integer type,
1995 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1996
1997 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1998 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1999 constant. TYPE must be a scalar or vector floating point type. CST must be of
2000 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
2001 of the same number of elements. If the value won't fit in the floating point
2002 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2003
2004 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2005 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]2006 constant. TYPE must be a scalar or vector floating point type. CST must be of
2007 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
2008 of the same number of elements. If the value won't fit in the floating point
2009 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2010
2011 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2012 <dd>Convert a pointer typed constant to the corresponding integer constant
2013 TYPE must be an integer type. CST must be of pointer type. The CST value is
2014 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
2015
2016 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
2017 <dd>Convert a integer constant to a pointer constant. TYPE must be a
2018 pointer type. CST must be of integer type. The CST value is zero extended,
2019 truncated, or unchanged to make it fit in a pointer size. This one is
2020 <i>really</i> dangerous!</dd>
2021
2022 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2023 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2024 are the same as those for the <a href="#i_bitcast">bitcast
2025 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2026
2027 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
2028
2029 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
2030 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2031 instruction, the index list may have zero or more indexes, which are required
2032 to make sense for the type of "CSTPTR".</dd>
2033
2034 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
2035
2036 <dd>Perform the <a href="#i_select">select operation</a> on
2037 constants.</dd>
2038
2039 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2040 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2041
2042 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2043 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2044
2045 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
2046
2047 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2048 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2049
2050 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
2051
2052 <dd>Perform the <a href="#i_insertelement">insertelement
2053 operation</a> on constants.</dd>
2054
2055
2056 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
2057
2058 <dd>Perform the <a href="#i_shufflevector">shufflevector
2059 operation</a> on constants.</dd>
2060
2061 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
2062
2063 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2064 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
2065 binary</a> operations. The constraints on operands are the same as those for
2066 the corresponding instruction (e.g. no bitwise operations on floating point
2067 values are allowed).</dd>
2068</dl>
2069</div>
2070
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2071<!-- ======================================================================= -->
2072<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2073</div>
2074
2075<div class="doc_text">
2076
2077<p>Embedded metadata provides a way to attach arbitrary data to the
2078instruction stream without affecting the behaviour of the program. There are
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2079two metadata primitives, strings and nodes. All metadata has the
2080<tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2081point ('<tt>!</tt>').
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2082</p>
2083
2084<p>A metadata string is a string surrounded by double quotes. It can contain
2085any character by escaping non-printable characters with "\xx" where "xx" is
2086the two digit hex code. For example: "<tt>!"test\00"</tt>".
2087</p>
2088
2089<p>Metadata nodes are represented with notation similar to structure constants
2090(a comma separated list of elements, surrounded by braces and preceeded by an
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2091exclamation point). For example: "<tt>!{ metadata !"test\00", i32 10}</tt>".
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2092</p>
2093
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2094<p>A metadata node will attempt to track changes to the values it holds. In
2095the event that a value is deleted, it will be replaced with a typeless
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2096"<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2097
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2098<p>Optimizations may rely on metadata to provide additional information about
2099the program that isn't available in the instructions, or that isn't easily
2100computable. Similarly, the code generator may expect a certain metadata format
2101to be used to express debugging information.</p>
2102</div>
2103
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2104<!-- *********************************************************************** -->
2105<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2106<!-- *********************************************************************** -->
2107
2108<!-- ======================================================================= -->
2109<div class="doc_subsection">
2110<a name="inlineasm">Inline Assembler Expressions</a>
2111</div>
2112
2113<div class="doc_text">
2114
2115<p>
2116LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2117Module-Level Inline Assembly</a>) through the use of a special value. This
2118value represents the inline assembler as a string (containing the instructions
2119to emit), a list of operand constraints (stored as a string), and a flag that
2120indicates whether or not the inline asm expression has side effects. An example
2121inline assembler expression is:
2122</p>
2123
2124<div class="doc_code">
2125<pre>
2126i32 (i32) asm "bswap $0", "=r,r"
2127</pre>
2128</div>
2129
2130<p>
2131Inline assembler expressions may <b>only</b> be used as the callee operand of
2132a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2133</p>
2134
2135<div class="doc_code">
2136<pre>
2137%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2138</pre>
2139</div>
2140
2141<p>
2142Inline asms with side effects not visible in the constraint list must be marked
2143as having side effects. This is done through the use of the
2144'<tt>sideeffect</tt>' keyword, like so:
2145</p>
2146
2147<div class="doc_code">
2148<pre>
2149call void asm sideeffect "eieio", ""()
2150</pre>
2151</div>
2152
2153<p>TODO: The format of the asm and constraints string still need to be
2154documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2155need to be documented). This is probably best done by reference to another
2156document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2157</p>
2158
2159</div>
2160
2161<!-- *********************************************************************** -->
2162<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2163<!-- *********************************************************************** -->
2164
2165<div class="doc_text">
2166
2167<p>The LLVM instruction set consists of several different
2168classifications of instructions: <a href="#terminators">terminator
2169instructions</a>, <a href="#binaryops">binary instructions</a>,
2170<a href="#bitwiseops">bitwise binary instructions</a>, <a
2171 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2172instructions</a>.</p>
2173
2174</div>
2175
2176<!-- ======================================================================= -->
2177<div class="doc_subsection"> <a name="terminators">Terminator
2178Instructions</a> </div>
2179
2180<div class="doc_text">
2181
2182<p>As mentioned <a href="#functionstructure">previously</a>, every
2183basic block in a program ends with a "Terminator" instruction, which
2184indicates which block should be executed after the current block is
2185finished. These terminator instructions typically yield a '<tt>void</tt>'
2186value: they produce control flow, not values (the one exception being
2187the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2188<p>There are six different terminator instructions: the '<a
2189 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2190instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2191the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2192 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2193 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2194
2195</div>
2196
2197<!-- _______________________________________________________________________ -->
2198<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2199Instruction</a> </div>
2200<div class="doc_text">
2201<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2202<pre>
2203 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2204 ret void <i>; Return from void function</i>
2205</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2206
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2207<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2208
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2209<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2210optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2211<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2212returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2213control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2215<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2216
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2217<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2218the return value. The type of the return value must be a
2219'<a href="#t_firstclass">first class</a>' type.</p>
2220
2221<p>A function is not <a href="#wellformed">well formed</a> if
2222it it has a non-void return type and contains a '<tt>ret</tt>'
2223instruction with no return value or a return value with a type that
2224does not match its type, or if it has a void return type and contains
2225a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2227<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2229<p>When the '<tt>ret</tt>' instruction is executed, control flow
2230returns back to the calling function's context. If the caller is a "<a
2231 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2232the instruction after the call. If the caller was an "<a
2233 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2234at the beginning of the "normal" destination block. If the instruction
2235returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2236return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2238<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2239
2240<pre>
2241 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2242 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2243 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2244</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2245
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2246<p>Note that the code generator does not yet fully support large
2247 return values. The specific sizes that are currently supported are
2248 dependent on the target. For integers, on 32-bit targets the limit
2249 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2250 For aggregate types, the current limits are dependent on the element
2251 types; for example targets are often limited to 2 total integer
2252 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2254</div>
2255<!-- _______________________________________________________________________ -->
2256<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2257<div class="doc_text">
2258<h5>Syntax:</h5>
2259<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2260</pre>
2261<h5>Overview:</h5>
2262<p>The '<tt>br</tt>' instruction is used to cause control flow to
2263transfer to a different basic block in the current function. There are
2264two forms of this instruction, corresponding to a conditional branch
2265and an unconditional branch.</p>
2266<h5>Arguments:</h5>
2267<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2268single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2269unconditional form of the '<tt>br</tt>' instruction takes a single
2270'<tt>label</tt>' value as a target.</p>
2271<h5>Semantics:</h5>
2272<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2273argument is evaluated. If the value is <tt>true</tt>, control flows
2274to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2275control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2276<h5>Example:</h5>
Chris Lattner95127832009-05-09 18:11:50 +0000[diff] [blame]2277<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2278 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2279</div>
2280<!-- _______________________________________________________________________ -->
2281<div class="doc_subsubsection">
2282 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2283</div>
2284
2285<div class="doc_text">
2286<h5>Syntax:</h5>
2287
2288<pre>
2289 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2290</pre>
2291
2292<h5>Overview:</h5>
2293
2294<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2295several different places. It is a generalization of the '<tt>br</tt>'
2296instruction, allowing a branch to occur to one of many possible
2297destinations.</p>
2298
2299
2300<h5>Arguments:</h5>
2301
2302<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2303comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2304an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2305table is not allowed to contain duplicate constant entries.</p>
2306
2307<h5>Semantics:</h5>
2308
2309<p>The <tt>switch</tt> instruction specifies a table of values and
2310destinations. When the '<tt>switch</tt>' instruction is executed, this
2311table is searched for the given value. If the value is found, control flow is
2312transfered to the corresponding destination; otherwise, control flow is
2313transfered to the default destination.</p>
2314
2315<h5>Implementation:</h5>
2316
2317<p>Depending on properties of the target machine and the particular
2318<tt>switch</tt> instruction, this instruction may be code generated in different
2319ways. For example, it could be generated as a series of chained conditional
2320branches or with a lookup table.</p>
2321
2322<h5>Example:</h5>
2323
2324<pre>
2325 <i>; Emulate a conditional br instruction</i>
2326 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2327 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2328
2329 <i>; Emulate an unconditional br instruction</i>
2330 switch i32 0, label %dest [ ]
2331
2332 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2333 switch i32 %val, label %otherwise [ i32 0, label %onzero
2334 i32 1, label %onone
2335 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2336</pre>
2337</div>
2338
2339<!-- _______________________________________________________________________ -->
2340<div class="doc_subsubsection">
2341 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2342</div>
2343
2344<div class="doc_text">
2345
2346<h5>Syntax:</h5>
2347
2348<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2349 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2350 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2351</pre>
2352
2353<h5>Overview:</h5>
2354
2355<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2356function, with the possibility of control flow transfer to either the
2357'<tt>normal</tt>' label or the
2358'<tt>exception</tt>' label. If the callee function returns with the
2359"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2360"normal" label. If the callee (or any indirect callees) returns with the "<a
2361href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2362continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2363
2364<h5>Arguments:</h5>
2365
2366<p>This instruction requires several arguments:</p>
2367
2368<ol>
2369 <li>
2370 The optional "cconv" marker indicates which <a href="#callingconv">calling
2371 convention</a> the call should use. If none is specified, the call defaults
2372 to using C calling conventions.
2373 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2374
2375 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2376 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2377 and '<tt>inreg</tt>' attributes are valid here.</li>
2378
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2379 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2380 function value being invoked. In most cases, this is a direct function
2381 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2382 an arbitrary pointer to function value.
2383 </li>
2384
2385 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2386 function to be invoked. </li>
2387
2388 <li>'<tt>function args</tt>': argument list whose types match the function
2389 signature argument types. If the function signature indicates the function
2390 accepts a variable number of arguments, the extra arguments can be
2391 specified. </li>
2392
2393 <li>'<tt>normal label</tt>': the label reached when the called function
2394 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2395
2396 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2397 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2398
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2399 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2400 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2401 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2402</ol>
2403
2404<h5>Semantics:</h5>
2405
2406<p>This instruction is designed to operate as a standard '<tt><a
2407href="#i_call">call</a></tt>' instruction in most regards. The primary
2408difference is that it establishes an association with a label, which is used by
2409the runtime library to unwind the stack.</p>
2410
2411<p>This instruction is used in languages with destructors to ensure that proper
2412cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2413exception. Additionally, this is important for implementation of
2414'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2415
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]2416<p>For the purposes of the SSA form, the definition of the value
2417returned by the '<tt>invoke</tt>' instruction is deemed to occur on
2418the edge from the current block to the "normal" label. If the callee
2419unwinds then no return value is available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2420
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2421<h5>Example:</h5>
2422<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2423 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2424 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2425 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2426 unwind label %TestCleanup <i>; {i32}:retval set</i>
2427</pre>
2428</div>
2429
2430
2431<!-- _______________________________________________________________________ -->
2432
2433<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2434Instruction</a> </div>
2435
2436<div class="doc_text">
2437
2438<h5>Syntax:</h5>
2439<pre>
2440 unwind
2441</pre>
2442
2443<h5>Overview:</h5>
2444
2445<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2446at the first callee in the dynamic call stack which used an <a
2447href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2448primarily used to implement exception handling.</p>
2449
2450<h5>Semantics:</h5>
2451
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2452<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2453immediately halt. The dynamic call stack is then searched for the first <a
2454href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2455execution continues at the "exceptional" destination block specified by the
2456<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2457dynamic call chain, undefined behavior results.</p>
2458</div>
2459
2460<!-- _______________________________________________________________________ -->
2461
2462<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2463Instruction</a> </div>
2464
2465<div class="doc_text">
2466
2467<h5>Syntax:</h5>
2468<pre>
2469 unreachable
2470</pre>
2471
2472<h5>Overview:</h5>
2473
2474<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2475instruction is used to inform the optimizer that a particular portion of the
2476code is not reachable. This can be used to indicate that the code after a
2477no-return function cannot be reached, and other facts.</p>
2478
2479<h5>Semantics:</h5>
2480
2481<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2482</div>
2483
2484
2485
2486<!-- ======================================================================= -->
2487<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2488<div class="doc_text">
2489<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2490program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2491produce a single value. The operands might represent
2492multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2493The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494<p>There are several different binary operators:</p>
2495</div>
2496<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2497<div class="doc_subsubsection">
2498 <a name="i_add">'<tt>add</tt>' Instruction</a>
2499</div>
2500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2503<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2504
2505<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2506 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2507</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2509<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2510
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2511<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2513<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2514
2515<p>The two arguments to the '<tt>add</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2516 href="#t_integer">integer</a> or
2517 <a href="#t_vector">vector</a> of integer values. Both arguments must
2518 have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2519
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2520<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2521
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2522<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2523
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2524<p>If the sum has unsigned overflow, the result returned is the
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2525mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2526the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2527
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2528<p>Because LLVM integers use a two's complement representation, this
2529instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2530
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2531<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2532
2533<pre>
2534 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2535</pre>
2536</div>
2537<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2538<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2539 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2540</div>
2541
2542<div class="doc_text">
2543
2544<h5>Syntax:</h5>
2545
2546<pre>
2547 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2548</pre>
2549
2550<h5>Overview:</h5>
2551
2552<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2553
2554<h5>Arguments:</h5>
2555
2556<p>The two arguments to the '<tt>fadd</tt>' instruction must be
2557<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2558floating point values. Both arguments must have identical types.</p>
2559
2560<h5>Semantics:</h5>
2561
2562<p>The value produced is the floating point sum of the two operands.</p>
2563
2564<h5>Example:</h5>
2565
2566<pre>
2567 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2568</pre>
2569</div>
2570<!-- _______________________________________________________________________ -->
2571<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2572 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2573</div>
2574
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2575<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2578
2579<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2580 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2581</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2585<p>The '<tt>sub</tt>' instruction returns the difference of its two
2586operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2587
2588<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2589'<tt>neg</tt>' instruction present in most other intermediate
2590representations.</p>
2591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2592<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2593
2594<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2595 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2596 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2598<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2599
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2600<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2601
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2602<p>If the difference has unsigned overflow, the result returned is the
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2603mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2604the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2605
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2606<p>Because LLVM integers use a two's complement representation, this
2607instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2608
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2609<h5>Example:</h5>
2610<pre>
2611 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2612 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2613</pre>
2614</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2617<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2618 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2619</div>
2620
2621<div class="doc_text">
2622
2623<h5>Syntax:</h5>
2624
2625<pre>
2626 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2627</pre>
2628
2629<h5>Overview:</h5>
2630
2631<p>The '<tt>fsub</tt>' instruction returns the difference of its two
2632operands.</p>
2633
2634<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
2635'<tt>fneg</tt>' instruction present in most other intermediate
2636representations.</p>
2637
2638<h5>Arguments:</h5>
2639
2640<p>The two arguments to the '<tt>fsub</tt>' instruction must be <a
2641 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2642 of floating point values. Both arguments must have identical types.</p>
2643
2644<h5>Semantics:</h5>
2645
2646<p>The value produced is the floating point difference of the two operands.</p>
2647
2648<h5>Example:</h5>
2649<pre>
2650 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2651 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2652</pre>
2653</div>
2654
2655<!-- _______________________________________________________________________ -->
2656<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2657 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2658</div>
2659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2663<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2664</pre>
2665<h5>Overview:</h5>
2666<p>The '<tt>mul</tt>' instruction returns the product of its two
2667operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2669<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2670
2671<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2672href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2673values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2674
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2675<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2676
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2677<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2678
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2679<p>If the result of the multiplication has unsigned overflow,
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2680the result returned is the mathematical result modulo
26812<sup>n</sup>, where n is the bit width of the result.</p>
2682<p>Because LLVM integers use a two's complement representation, and the
2683result is the same width as the operands, this instruction returns the
2684correct result for both signed and unsigned integers. If a full product
2685(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2686should be sign-extended or zero-extended as appropriate to the
2687width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2688<h5>Example:</h5>
2689<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2690</pre>
2691</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2693<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2694<div class="doc_subsubsection">
2695 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2696</div>
2697
2698<div class="doc_text">
2699
2700<h5>Syntax:</h5>
2701<pre> &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2702</pre>
2703<h5>Overview:</h5>
2704<p>The '<tt>fmul</tt>' instruction returns the product of its two
2705operands.</p>
2706
2707<h5>Arguments:</h5>
2708
2709<p>The two arguments to the '<tt>fmul</tt>' instruction must be
2710<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2711of floating point values. Both arguments must have identical types.</p>
2712
2713<h5>Semantics:</h5>
2714
2715<p>The value produced is the floating point product of the two operands.</p>
2716
2717<h5>Example:</h5>
2718<pre> &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
2719</pre>
2720</div>
2721
2722<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2723<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2724</a></div>
2725<div class="doc_text">
2726<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2727<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2728</pre>
2729<h5>Overview:</h5>
2730<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2731operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2732
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2733<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2734
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2735<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2736<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2737values. Both arguments must have identical types.</p>
2738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2739<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2740
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2741<p>The value produced is the unsigned integer quotient of the two operands.</p>
2742<p>Note that unsigned integer division and signed integer division are distinct
2743operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2744<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2745<h5>Example:</h5>
2746<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2747</pre>
2748</div>
2749<!-- _______________________________________________________________________ -->
2750<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2751</a> </div>
2752<div class="doc_text">
2753<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2754<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2755 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2758<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2759
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2760<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2761operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2763<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2764
2765<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2766<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2767values. Both arguments must have identical types.</p>
2768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2769<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2770<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2771<p>Note that signed integer division and unsigned integer division are distinct
2772operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2773<p>Division by zero leads to undefined behavior. Overflow also leads to
2774undefined behavior; this is a rare case, but can occur, for example,
2775by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2776<h5>Example:</h5>
2777<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2778</pre>
2779</div>
2780<!-- _______________________________________________________________________ -->
2781<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2782Instruction</a> </div>
2783<div class="doc_text">
2784<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2785<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2786 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2787</pre>
2788<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2790<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2791operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2792
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2793<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2795<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2796<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2797of floating point values. Both arguments must have identical types.</p>
2798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2799<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2801<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2804
2805<pre>
2806 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2807</pre>
2808</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2809
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2810<!-- _______________________________________________________________________ -->
2811<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2812</div>
2813<div class="doc_text">
2814<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2815<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2816</pre>
2817<h5>Overview:</h5>
2818<p>The '<tt>urem</tt>' instruction returns the remainder from the
2819unsigned division of its two arguments.</p>
2820<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2821<p>The two arguments to the '<tt>urem</tt>' instruction must be
2822<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2823values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2824<h5>Semantics:</h5>
2825<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2826This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2827<p>Note that unsigned integer remainder and signed integer remainder are
2828distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2829<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2830<h5>Example:</h5>
2831<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2832</pre>
2833
2834</div>
2835<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2836<div class="doc_subsubsection">
2837 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2838</div>
2839
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2840<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2842<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2843
2844<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2845 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2846</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2848<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2850<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2851signed division of its two operands. This instruction can also take
2852<a href="#t_vector">vector</a> versions of the values in which case
2853the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2855<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2856
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2857<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2858<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2859values. Both arguments must have identical types.</p>
2860
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2861<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2863<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2864has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2865operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2866a value. For more information about the difference, see <a
2867 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2868Math Forum</a>. For a table of how this is implemented in various languages,
2869please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2870Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2871<p>Note that signed integer remainder and unsigned integer remainder are
2872distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2873<p>Taking the remainder of a division by zero leads to undefined behavior.
2874Overflow also leads to undefined behavior; this is a rare case, but can occur,
2875for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2876(The remainder doesn't actually overflow, but this rule lets srem be
2877implemented using instructions that return both the result of the division
2878and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2879<h5>Example:</h5>
2880<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2881</pre>
2882
2883</div>
2884<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2885<div class="doc_subsubsection">
2886 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2887
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2888<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2890<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2891<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2892</pre>
2893<h5>Overview:</h5>
2894<p>The '<tt>frem</tt>' instruction returns the remainder from the
2895division of its two operands.</p>
2896<h5>Arguments:</h5>
2897<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2898<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2899of floating point values. Both arguments must have identical types.</p>
2900
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2901<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2902
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2903<p>This instruction returns the <i>remainder</i> of a division.
2904The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2906<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2907
2908<pre>
2909 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2910</pre>
2911</div>
2912
2913<!-- ======================================================================= -->
2914<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2915Operations</a> </div>
2916<div class="doc_text">
2917<p>Bitwise binary operators are used to do various forms of
2918bit-twiddling in a program. They are generally very efficient
2919instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2920instructions. They require two operands of the same type, execute an operation on them,
2921and produce a single value. The resulting value is the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2922</div>
2923
2924<!-- _______________________________________________________________________ -->
2925<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2926Instruction</a> </div>
2927<div class="doc_text">
2928<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2929<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2930</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2931
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2932<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2933
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2934<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2935the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2936
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2937<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2939<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2940 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2941type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2942
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2943<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2944
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2945<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2946where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2947equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2948If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2949corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2951<h5>Example:</h5><pre>
2952 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2953 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2954 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2955 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2956 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2957</pre>
2958</div>
2959<!-- _______________________________________________________________________ -->
2960<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2961Instruction</a> </div>
2962<div class="doc_text">
2963<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2964<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2965</pre>
2966
2967<h5>Overview:</h5>
2968<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2969operand shifted to the right a specified number of bits with zero fill.</p>
2970
2971<h5>Arguments:</h5>
2972<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2973<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2974type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2975
2976<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2977
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2978<p>This instruction always performs a logical shift right operation. The most
2979significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2980shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2981the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2982vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2983amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2984
2985<h5>Example:</h5>
2986<pre>
2987 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2988 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2989 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2990 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2991 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2992 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2993</pre>
2994</div>
2995
2996<!-- _______________________________________________________________________ -->
2997<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2998Instruction</a> </div>
2999<div class="doc_text">
3000
3001<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3002<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3003</pre>
3004
3005<h5>Overview:</h5>
3006<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3007operand shifted to the right a specified number of bits with sign extension.</p>
3008
3009<h5>Arguments:</h5>
3010<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]3011<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3012type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3013
3014<h5>Semantics:</h5>
3015<p>This instruction always performs an arithmetic shift right operation,
3016The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3017of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]3018larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
3019arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
3020corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3021
3022<h5>Example:</h5>
3023<pre>
3024 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3025 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3026 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3027 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3028 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3029 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3030</pre>
3031</div>
3032
3033<!-- _______________________________________________________________________ -->
3034<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3035Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3037<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3039<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3040
3041<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3042 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3043</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3044
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3045<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3046
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3047<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
3048its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3049
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3050<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3051
3052<p>The two arguments to the '<tt>and</tt>' instruction must be
3053<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3054values. Both arguments must have identical types.</p>
3055
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3056<h5>Semantics:</h5>
3057<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
3058<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3059<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3060<table border="1" cellspacing="0" cellpadding="4">
3061 <tbody>
3062 <tr>
3063 <td>In0</td>
3064 <td>In1</td>
3065 <td>Out</td>
3066 </tr>
3067 <tr>
3068 <td>0</td>
3069 <td>0</td>
3070 <td>0</td>
3071 </tr>
3072 <tr>
3073 <td>0</td>
3074 <td>1</td>
3075 <td>0</td>
3076 </tr>
3077 <tr>
3078 <td>1</td>
3079 <td>0</td>
3080 <td>0</td>
3081 </tr>
3082 <tr>
3083 <td>1</td>
3084 <td>1</td>
3085 <td>1</td>
3086 </tr>
3087 </tbody>
3088</table>
3089</div>
3090<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3091<pre>
3092 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3093 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3094 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3095</pre>
3096</div>
3097<!-- _______________________________________________________________________ -->
3098<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
3099<div class="doc_text">
3100<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3101<pre> &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3102</pre>
3103<h5>Overview:</h5>
3104<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
3105or of its two operands.</p>
3106<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3107
3108<p>The two arguments to the '<tt>or</tt>' instruction must be
3109<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3110values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3111<h5>Semantics:</h5>
3112<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
3113<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3114<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3115<table border="1" cellspacing="0" cellpadding="4">
3116 <tbody>
3117 <tr>
3118 <td>In0</td>
3119 <td>In1</td>
3120 <td>Out</td>
3121 </tr>
3122 <tr>
3123 <td>0</td>
3124 <td>0</td>
3125 <td>0</td>
3126 </tr>
3127 <tr>
3128 <td>0</td>
3129 <td>1</td>
3130 <td>1</td>
3131 </tr>
3132 <tr>
3133 <td>1</td>
3134 <td>0</td>
3135 <td>1</td>
3136 </tr>
3137 <tr>
3138 <td>1</td>
3139 <td>1</td>
3140 <td>1</td>
3141 </tr>
3142 </tbody>
3143</table>
3144</div>
3145<h5>Example:</h5>
3146<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
3147 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3148 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3149</pre>
3150</div>
3151<!-- _______________________________________________________________________ -->
3152<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3153Instruction</a> </div>
3154<div class="doc_text">
3155<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3156<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3157</pre>
3158<h5>Overview:</h5>
3159<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
3160or of its two operands. The <tt>xor</tt> is used to implement the
3161"one's complement" operation, which is the "~" operator in C.</p>
3162<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3163<p>The two arguments to the '<tt>xor</tt>' instruction must be
3164<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3165values. Both arguments must have identical types.</p>
3166
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3167<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3168
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3169<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
3170<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3171<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172<table border="1" cellspacing="0" cellpadding="4">
3173 <tbody>
3174 <tr>
3175 <td>In0</td>
3176 <td>In1</td>
3177 <td>Out</td>
3178 </tr>
3179 <tr>
3180 <td>0</td>
3181 <td>0</td>
3182 <td>0</td>
3183 </tr>
3184 <tr>
3185 <td>0</td>
3186 <td>1</td>
3187 <td>1</td>
3188 </tr>
3189 <tr>
3190 <td>1</td>
3191 <td>0</td>
3192 <td>1</td>
3193 </tr>
3194 <tr>
3195 <td>1</td>
3196 <td>1</td>
3197 <td>0</td>
3198 </tr>
3199 </tbody>
3200</table>
3201</div>
3202<p> </p>
3203<h5>Example:</h5>
3204<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3205 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3206 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3207 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3208</pre>
3209</div>
3210
3211<!-- ======================================================================= -->
3212<div class="doc_subsection">
3213 <a name="vectorops">Vector Operations</a>
3214</div>
3215
3216<div class="doc_text">
3217
3218<p>LLVM supports several instructions to represent vector operations in a
3219target-independent manner. These instructions cover the element-access and
3220vector-specific operations needed to process vectors effectively. While LLVM
3221does directly support these vector operations, many sophisticated algorithms
3222will want to use target-specific intrinsics to take full advantage of a specific
3223target.</p>
3224
3225</div>
3226
3227<!-- _______________________________________________________________________ -->
3228<div class="doc_subsubsection">
3229 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3230</div>
3231
3232<div class="doc_text">
3233
3234<h5>Syntax:</h5>
3235
3236<pre>
3237 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3238</pre>
3239
3240<h5>Overview:</h5>
3241
3242<p>
3243The '<tt>extractelement</tt>' instruction extracts a single scalar
3244element from a vector at a specified index.
3245</p>
3246
3247
3248<h5>Arguments:</h5>
3249
3250<p>
3251The first operand of an '<tt>extractelement</tt>' instruction is a
3252value of <a href="#t_vector">vector</a> type. The second operand is
3253an index indicating the position from which to extract the element.
3254The index may be a variable.</p>
3255
3256<h5>Semantics:</h5>
3257
3258<p>
3259The result is a scalar of the same type as the element type of
3260<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3261<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3262results are undefined.
3263</p>
3264
3265<h5>Example:</h5>
3266
3267<pre>
3268 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3269</pre>
3270</div>
3271
3272
3273<!-- _______________________________________________________________________ -->
3274<div class="doc_subsubsection">
3275 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3276</div>
3277
3278<div class="doc_text">
3279
3280<h5>Syntax:</h5>
3281
3282<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3283 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3284</pre>
3285
3286<h5>Overview:</h5>
3287
3288<p>
3289The '<tt>insertelement</tt>' instruction inserts a scalar
3290element into a vector at a specified index.
3291</p>
3292
3293
3294<h5>Arguments:</h5>
3295
3296<p>
3297The first operand of an '<tt>insertelement</tt>' instruction is a
3298value of <a href="#t_vector">vector</a> type. The second operand is a
3299scalar value whose type must equal the element type of the first
3300operand. The third operand is an index indicating the position at
3301which to insert the value. The index may be a variable.</p>
3302
3303<h5>Semantics:</h5>
3304
3305<p>
3306The result is a vector of the same type as <tt>val</tt>. Its
3307element values are those of <tt>val</tt> except at position
3308<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3309exceeds the length of <tt>val</tt>, the results are undefined.
3310</p>
3311
3312<h5>Example:</h5>
3313
3314<pre>
3315 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3316</pre>
3317</div>
3318
3319<!-- _______________________________________________________________________ -->
3320<div class="doc_subsubsection">
3321 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3322</div>
3323
3324<div class="doc_text">
3325
3326<h5>Syntax:</h5>
3327
3328<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3329 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3330</pre>
3331
3332<h5>Overview:</h5>
3333
3334<p>
3335The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3336from two input vectors, returning a vector with the same element type as
3337the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3338</p>
3339
3340<h5>Arguments:</h5>
3341
3342<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3343The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3344with types that match each other. The third argument is a shuffle mask whose
3345element type is always 'i32'. The result of the instruction is a vector whose
3346length is the same as the shuffle mask and whose element type is the same as
3347the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3348</p>
3349
3350<p>
3351The shuffle mask operand is required to be a constant vector with either
3352constant integer or undef values.
3353</p>
3354
3355<h5>Semantics:</h5>
3356
3357<p>
3358The elements of the two input vectors are numbered from left to right across
3359both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3360the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361gets. The element selector may be undef (meaning "don't care") and the second
3362operand may be undef if performing a shuffle from only one vector.
3363</p>
3364
3365<h5>Example:</h5>
3366
3367<pre>
3368 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3369 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3370 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3371 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3372 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3373 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3374 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3375 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3376</pre>
3377</div>
3378
3379
3380<!-- ======================================================================= -->
3381<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3382 <a name="aggregateops">Aggregate Operations</a>
3383</div>
3384
3385<div class="doc_text">
3386
3387<p>LLVM supports several instructions for working with aggregate values.
3388</p>
3389
3390</div>
3391
3392<!-- _______________________________________________________________________ -->
3393<div class="doc_subsubsection">
3394 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3395</div>
3396
3397<div class="doc_text">
3398
3399<h5>Syntax:</h5>
3400
3401<pre>
3402 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3403</pre>
3404
3405<h5>Overview:</h5>
3406
3407<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3408The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3409or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3410</p>
3411
3412
3413<h5>Arguments:</h5>
3414
3415<p>
3416The first operand of an '<tt>extractvalue</tt>' instruction is a
3417value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3418type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3419in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3420'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3421</p>
3422
3423<h5>Semantics:</h5>
3424
3425<p>
3426The result is the value at the position in the aggregate specified by
3427the index operands.
3428</p>
3429
3430<h5>Example:</h5>
3431
3432<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3433 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3434</pre>
3435</div>
3436
3437
3438<!-- _______________________________________________________________________ -->
3439<div class="doc_subsubsection">
3440 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3441</div>
3442
3443<div class="doc_text">
3444
3445<h5>Syntax:</h5>
3446
3447<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3448 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3449</pre>
3450
3451<h5>Overview:</h5>
3452
3453<p>
3454The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3455into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3456</p>
3457
3458
3459<h5>Arguments:</h5>
3460
3461<p>
3462The first operand of an '<tt>insertvalue</tt>' instruction is a
3463value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3464The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3465The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3466indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3467indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3468'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3469The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3470by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3471</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3472
3473<h5>Semantics:</h5>
3474
3475<p>
3476The result is an aggregate of the same type as <tt>val</tt>. Its
3477value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3478specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3479</p>
3480
3481<h5>Example:</h5>
3482
3483<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3484 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3485</pre>
3486</div>
3487
3488
3489<!-- ======================================================================= -->
3490<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3491 <a name="memoryops">Memory Access and Addressing Operations</a>
3492</div>
3493
3494<div class="doc_text">
3495
3496<p>A key design point of an SSA-based representation is how it
3497represents memory. In LLVM, no memory locations are in SSA form, which
3498makes things very simple. This section describes how to read, write,
3499allocate, and free memory in LLVM.</p>
3500
3501</div>
3502
3503<!-- _______________________________________________________________________ -->
3504<div class="doc_subsubsection">
3505 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3506</div>
3507
3508<div class="doc_text">
3509
3510<h5>Syntax:</h5>
3511
3512<pre>
3513 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3514</pre>
3515
3516<h5>Overview:</h5>
3517
3518<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3519heap and returns a pointer to it. The object is always allocated in the generic
3520address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3521
3522<h5>Arguments:</h5>
3523
3524<p>The '<tt>malloc</tt>' instruction allocates
3525<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3526bytes of memory from the operating system and returns a pointer of the
3527appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3528number of elements allocated, otherwise "NumElements" is defaulted to be one.
Duncan Sandsb38ce6f2009-06-20 13:26:06 +0000[diff] [blame]3529If a constant alignment is specified, the value result of the allocation is
3530guaranteed to be aligned to at least that boundary. If not specified, or if
3531zero, the target can choose to align the allocation on any convenient boundary
3532compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3533
3534<p>'<tt>type</tt>' must be a sized type.</p>
3535
3536<h5>Semantics:</h5>
3537
3538<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3539a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3540result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3541
3542<h5>Example:</h5>
3543
3544<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3545 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3546
3547 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3548 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3549 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3550 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3551 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3552</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3553
3554<p>Note that the code generator does not yet respect the
3555 alignment value.</p>
3556
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3557</div>
3558
3559<!-- _______________________________________________________________________ -->
3560<div class="doc_subsubsection">
3561 <a name="i_free">'<tt>free</tt>' Instruction</a>
3562</div>
3563
3564<div class="doc_text">
3565
3566<h5>Syntax:</h5>
3567
3568<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3569 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3570</pre>
3571
3572<h5>Overview:</h5>
3573
3574<p>The '<tt>free</tt>' instruction returns memory back to the unused
3575memory heap to be reallocated in the future.</p>
3576
3577<h5>Arguments:</h5>
3578
3579<p>'<tt>value</tt>' shall be a pointer value that points to a value
3580that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3581instruction.</p>
3582
3583<h5>Semantics:</h5>
3584
3585<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3586after this instruction executes. If the pointer is null, the operation
3587is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3588
3589<h5>Example:</h5>
3590
3591<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3592 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3593 free [4 x i8]* %array
3594</pre>
3595</div>
3596
3597<!-- _______________________________________________________________________ -->
3598<div class="doc_subsubsection">
3599 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3600</div>
3601
3602<div class="doc_text">
3603
3604<h5>Syntax:</h5>
3605
3606<pre>
3607 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3608</pre>
3609
3610<h5>Overview:</h5>
3611
3612<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3613currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3614returns to its caller. The object is always allocated in the generic address
3615space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3616
3617<h5>Arguments:</h5>
3618
3619<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3620bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3621appropriate type to the program. If "NumElements" is specified, it is the
3622number of elements allocated, otherwise "NumElements" is defaulted to be one.
Duncan Sandsb38ce6f2009-06-20 13:26:06 +0000[diff] [blame]3623If a constant alignment is specified, the value result of the allocation is
3624guaranteed to be aligned to at least that boundary. If not specified, or if
3625zero, the target can choose to align the allocation on any convenient boundary
3626compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3627
3628<p>'<tt>type</tt>' may be any sized type.</p>
3629
3630<h5>Semantics:</h5>
3631
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3632<p>Memory is allocated; a pointer is returned. The operation is undefined if
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3633there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3634memory is automatically released when the function returns. The '<tt>alloca</tt>'
3635instruction is commonly used to represent automatic variables that must
3636have an address available. When the function returns (either with the <tt><a
3637 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3638instructions), the memory is reclaimed. Allocating zero bytes
3639is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3640
3641<h5>Example:</h5>
3642
3643<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3644 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3645 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3646 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3647 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3648</pre>
3649</div>
3650
3651<!-- _______________________________________________________________________ -->
3652<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3653Instruction</a> </div>
3654<div class="doc_text">
3655<h5>Syntax:</h5>
3656<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
3657<h5>Overview:</h5>
3658<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3659<h5>Arguments:</h5>
3660<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3661address from which to load. The pointer must point to a <a
3662 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3663marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3664the number or order of execution of this <tt>load</tt> with other
3665volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3666instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3667<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3668The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3669(that is, the alignment of the memory address). A value of 0 or an
3670omitted "align" argument means that the operation has the preferential
3671alignment for the target. It is the responsibility of the code emitter
3672to ensure that the alignment information is correct. Overestimating
3673the alignment results in an undefined behavior. Underestimating the
3674alignment may produce less efficient code. An alignment of 1 is always
3675safe.
3676</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3677<h5>Semantics:</h5>
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3678<p>The location of memory pointed to is loaded. If the value being loaded
3679is of scalar type then the number of bytes read does not exceed the minimum
3680number of bytes needed to hold all bits of the type. For example, loading an
3681<tt>i24</tt> reads at most three bytes. When loading a value of a type like
3682<tt>i20</tt> with a size that is not an integral number of bytes, the result
3683is undefined if the value was not originally written using a store of the
3684same type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3685<h5>Examples:</h5>
3686<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3687 <a
3688 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3689 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3690</pre>
3691</div>
3692<!-- _______________________________________________________________________ -->
3693<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3694Instruction</a> </div>
3695<div class="doc_text">
3696<h5>Syntax:</h5>
3697<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3698 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3699</pre>
3700<h5>Overview:</h5>
3701<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3702<h5>Arguments:</h5>
3703<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3704to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3705operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3706of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3707operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3708optimizer is not allowed to modify the number or order of execution of
3709this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3710 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3711<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3712The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3713(that is, the alignment of the memory address). A value of 0 or an
3714omitted "align" argument means that the operation has the preferential
3715alignment for the target. It is the responsibility of the code emitter
3716to ensure that the alignment information is correct. Overestimating
3717the alignment results in an undefined behavior. Underestimating the
3718alignment may produce less efficient code. An alignment of 1 is always
3719safe.
3720</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3721<h5>Semantics:</h5>
3722<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3723at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.
3724If '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes
3725written does not exceed the minimum number of bytes needed to hold all
3726bits of the type. For example, storing an <tt>i24</tt> writes at most
3727three bytes. When writing a value of a type like <tt>i20</tt> with a
3728size that is not an integral number of bytes, it is unspecified what
3729happens to the extra bits that do not belong to the type, but they will
3730typically be overwritten.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3731<h5>Example:</h5>
3732<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3733 store i32 3, i32* %ptr <i>; yields {void}</i>
3734 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3735</pre>
3736</div>
3737
3738<!-- _______________________________________________________________________ -->
3739<div class="doc_subsubsection">
3740 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3741</div>
3742
3743<div class="doc_text">
3744<h5>Syntax:</h5>
3745<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3746 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3747</pre>
3748
3749<h5>Overview:</h5>
3750
3751<p>
3752The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3753subelement of an aggregate data structure. It performs address calculation only
3754and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3755
3756<h5>Arguments:</h5>
3757
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3758<p>The first argument is always a pointer, and forms the basis of the
3759calculation. The remaining arguments are indices, that indicate which of the
3760elements of the aggregate object are indexed. The interpretation of each index
3761is dependent on the type being indexed into. The first index always indexes the
3762pointer value given as the first argument, the second index indexes a value of
3763the type pointed to (not necessarily the value directly pointed to, since the
3764first index can be non-zero), etc. The first type indexed into must be a pointer
3765value, subsequent types can be arrays, vectors and structs. Note that subsequent
3766types being indexed into can never be pointers, since that would require loading
3767the pointer before continuing calculation.</p>
3768
3769<p>The type of each index argument depends on the type it is indexing into.
3770When indexing into a (packed) structure, only <tt>i32</tt> integer
3771<b>constants</b> are allowed. When indexing into an array, pointer or vector,
Sanjiv Guptaa2e72d92009-04-27 03:21:00 +0000[diff] [blame]3772integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3773
3774<p>For example, let's consider a C code fragment and how it gets
3775compiled to LLVM:</p>
3776
3777<div class="doc_code">
3778<pre>
3779struct RT {
3780 char A;
3781 int B[10][20];
3782 char C;
3783};
3784struct ST {
3785 int X;
3786 double Y;
3787 struct RT Z;
3788};
3789
3790int *foo(struct ST *s) {
3791 return &amp;s[1].Z.B[5][13];
3792}
3793</pre>
3794</div>
3795
3796<p>The LLVM code generated by the GCC frontend is:</p>
3797
3798<div class="doc_code">
3799<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3800%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3801%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3802
3803define i32* %foo(%ST* %s) {
3804entry:
3805 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3806 ret i32* %reg
3807}
3808</pre>
3809</div>
3810
3811<h5>Semantics:</h5>
3812
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3813<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3814type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3815}</tt>' type, a structure. The second index indexes into the third element of
3816the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3817i8 }</tt>' type, another structure. The third index indexes into the second
3818element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3819array. The two dimensions of the array are subscripted into, yielding an
3820'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3821to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3822
3823<p>Note that it is perfectly legal to index partially through a
3824structure, returning a pointer to an inner element. Because of this,
3825the LLVM code for the given testcase is equivalent to:</p>
3826
3827<pre>
3828 define i32* %foo(%ST* %s) {
3829 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3830 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3831 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3832 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3833 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3834 ret i32* %t5
3835 }
3836</pre>
3837
Chris Lattner50609942009-03-09 20:55:18 +0000[diff] [blame]3838<p>Note that it is undefined to access an array out of bounds: array
3839and pointer indexes must always be within the defined bounds of the
3840array type when accessed with an instruction that dereferences the
3841pointer (e.g. a load or store instruction). The one exception for
3842this rule is zero length arrays. These arrays are defined to be
3843accessible as variable length arrays, which requires access beyond the
3844zero'th element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3845
3846<p>The getelementptr instruction is often confusing. For some more insight
3847into how it works, see <a href="GetElementPtr.html">the getelementptr
3848FAQ</a>.</p>
3849
3850<h5>Example:</h5>
3851
3852<pre>
3853 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3854 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3855 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3856 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3857 <i>; yields i8*:eptr</i>
3858 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]3859 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]3860 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3861</pre>
3862</div>
3863
3864<!-- ======================================================================= -->
3865<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3866</div>
3867<div class="doc_text">
3868<p>The instructions in this category are the conversion instructions (casting)
3869which all take a single operand and a type. They perform various bit conversions
3870on the operand.</p>
3871</div>
3872
3873<!-- _______________________________________________________________________ -->
3874<div class="doc_subsubsection">
3875 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3876</div>
3877<div class="doc_text">
3878
3879<h5>Syntax:</h5>
3880<pre>
3881 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3882</pre>
3883
3884<h5>Overview:</h5>
3885<p>
3886The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3887</p>
3888
3889<h5>Arguments:</h5>
3890<p>
3891The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3892be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3893and type of the result, which must be an <a href="#t_integer">integer</a>
3894type. The bit size of <tt>value</tt> must be larger than the bit size of
3895<tt>ty2</tt>. Equal sized types are not allowed.</p>
3896
3897<h5>Semantics:</h5>
3898<p>
3899The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3900and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3901larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3902It will always truncate bits.</p>
3903
3904<h5>Example:</h5>
3905<pre>
3906 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3907 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3908 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3909</pre>
3910</div>
3911
3912<!-- _______________________________________________________________________ -->
3913<div class="doc_subsubsection">
3914 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3915</div>
3916<div class="doc_text">
3917
3918<h5>Syntax:</h5>
3919<pre>
3920 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3921</pre>
3922
3923<h5>Overview:</h5>
3924<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3925<tt>ty2</tt>.</p>
3926
3927
3928<h5>Arguments:</h5>
3929<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3930<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3931also be of <a href="#t_integer">integer</a> type. The bit size of the
3932<tt>value</tt> must be smaller than the bit size of the destination type,
3933<tt>ty2</tt>.</p>
3934
3935<h5>Semantics:</h5>
3936<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3937bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3938
3939<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3940
3941<h5>Example:</h5>
3942<pre>
3943 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3944 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3945</pre>
3946</div>
3947
3948<!-- _______________________________________________________________________ -->
3949<div class="doc_subsubsection">
3950 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3951</div>
3952<div class="doc_text">
3953
3954<h5>Syntax:</h5>
3955<pre>
3956 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3957</pre>
3958
3959<h5>Overview:</h5>
3960<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3961
3962<h5>Arguments:</h5>
3963<p>
3964The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3965<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3966also be of <a href="#t_integer">integer</a> type. The bit size of the
3967<tt>value</tt> must be smaller than the bit size of the destination type,
3968<tt>ty2</tt>.</p>
3969
3970<h5>Semantics:</h5>
3971<p>
3972The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3973bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3974the type <tt>ty2</tt>.</p>
3975
3976<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3977
3978<h5>Example:</h5>
3979<pre>
3980 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3981 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3982</pre>
3983</div>
3984
3985<!-- _______________________________________________________________________ -->
3986<div class="doc_subsubsection">
3987 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3988</div>
3989
3990<div class="doc_text">
3991
3992<h5>Syntax:</h5>
3993
3994<pre>
3995 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3996</pre>
3997
3998<h5>Overview:</h5>
3999<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
4000<tt>ty2</tt>.</p>
4001
4002
4003<h5>Arguments:</h5>
4004<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
4005 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
4006cast it to. The size of <tt>value</tt> must be larger than the size of
4007<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4008<i>no-op cast</i>.</p>
4009
4010<h5>Semantics:</h5>
4011<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4012<a href="#t_floating">floating point</a> type to a smaller
4013<a href="#t_floating">floating point</a> type. If the value cannot fit within
4014the destination type, <tt>ty2</tt>, then the results are undefined.</p>
4015
4016<h5>Example:</h5>
4017<pre>
4018 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4019 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4020</pre>
4021</div>
4022
4023<!-- _______________________________________________________________________ -->
4024<div class="doc_subsubsection">
4025 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4026</div>
4027<div class="doc_text">
4028
4029<h5>Syntax:</h5>
4030<pre>
4031 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4032</pre>
4033
4034<h5>Overview:</h5>
4035<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
4036floating point value.</p>
4037
4038<h5>Arguments:</h5>
4039<p>The '<tt>fpext</tt>' instruction takes a
4040<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
4041and a <a href="#t_floating">floating point</a> type to cast it to. The source
4042type must be smaller than the destination type.</p>
4043
4044<h5>Semantics:</h5>
4045<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
4046<a href="#t_floating">floating point</a> type to a larger
4047<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4048used to make a <i>no-op cast</i> because it always changes bits. Use
4049<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
4050
4051<h5>Example:</h5>
4052<pre>
4053 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4054 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4055</pre>
4056</div>
4057
4058<!-- _______________________________________________________________________ -->
4059<div class="doc_subsubsection">
4060 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4061</div>
4062<div class="doc_text">
4063
4064<h5>Syntax:</h5>
4065<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4066 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4067</pre>
4068
4069<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4070<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4071unsigned integer equivalent of type <tt>ty2</tt>.
4072</p>
4073
4074<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4075<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4076scalar or vector <a href="#t_floating">floating point</a> value, and a type
4077to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4078type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4079vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4080
4081<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4082<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4083<a href="#t_floating">floating point</a> operand into the nearest (rounding
4084towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
4085the results are undefined.</p>
4086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4087<h5>Example:</h5>
4088<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4089 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4090 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4091 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4092</pre>
4093</div>
4094
4095<!-- _______________________________________________________________________ -->
4096<div class="doc_subsubsection">
4097 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4098</div>
4099<div class="doc_text">
4100
4101<h5>Syntax:</h5>
4102<pre>
4103 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4104</pre>
4105
4106<h5>Overview:</h5>
4107<p>The '<tt>fptosi</tt>' instruction converts
4108<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
4109</p>
4110
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4111<h5>Arguments:</h5>
4112<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4113scalar or vector <a href="#t_floating">floating point</a> value, and a type
4114to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4115type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4116vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4117
4118<h5>Semantics:</h5>
4119<p>The '<tt>fptosi</tt>' instruction converts its
4120<a href="#t_floating">floating point</a> operand into the nearest (rounding
4121towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4122the results are undefined.</p>
4123
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4124<h5>Example:</h5>
4125<pre>
4126 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4127 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4128 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4129</pre>
4130</div>
4131
4132<!-- _______________________________________________________________________ -->
4133<div class="doc_subsubsection">
4134 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4135</div>
4136<div class="doc_text">
4137
4138<h5>Syntax:</h5>
4139<pre>
4140 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4141</pre>
4142
4143<h5>Overview:</h5>
4144<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
4145integer and converts that value to the <tt>ty2</tt> type.</p>
4146
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4147<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4148<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
4149scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4150to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4151type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4152floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4153
4154<h5>Semantics:</h5>
4155<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
4156integer quantity and converts it to the corresponding floating point value. If
4157the value cannot fit in the floating point value, the results are undefined.</p>
4158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4159<h5>Example:</h5>
4160<pre>
4161 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4162 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4163</pre>
4164</div>
4165
4166<!-- _______________________________________________________________________ -->
4167<div class="doc_subsubsection">
4168 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4169</div>
4170<div class="doc_text">
4171
4172<h5>Syntax:</h5>
4173<pre>
4174 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4175</pre>
4176
4177<h5>Overview:</h5>
4178<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
4179integer and converts that value to the <tt>ty2</tt> type.</p>
4180
4181<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4182<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
4183scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4184to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4185type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4186floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4187
4188<h5>Semantics:</h5>
4189<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
4190integer quantity and converts it to the corresponding floating point value. If
4191the value cannot fit in the floating point value, the results are undefined.</p>
4192
4193<h5>Example:</h5>
4194<pre>
4195 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4196 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4197</pre>
4198</div>
4199
4200<!-- _______________________________________________________________________ -->
4201<div class="doc_subsubsection">
4202 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4203</div>
4204<div class="doc_text">
4205
4206<h5>Syntax:</h5>
4207<pre>
4208 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4209</pre>
4210
4211<h5>Overview:</h5>
4212<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4213the integer type <tt>ty2</tt>.</p>
4214
4215<h5>Arguments:</h5>
4216<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4217must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4218<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4219
4220<h5>Semantics:</h5>
4221<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4222<tt>ty2</tt> by interpreting the pointer value as an integer and either
4223truncating or zero extending that value to the size of the integer type. If
4224<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4225<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4226are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4227change.</p>
4228
4229<h5>Example:</h5>
4230<pre>
4231 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4232 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4233</pre>
4234</div>
4235
4236<!-- _______________________________________________________________________ -->
4237<div class="doc_subsubsection">
4238 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4239</div>
4240<div class="doc_text">
4241
4242<h5>Syntax:</h5>
4243<pre>
4244 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4245</pre>
4246
4247<h5>Overview:</h5>
4248<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4249a pointer type, <tt>ty2</tt>.</p>
4250
4251<h5>Arguments:</h5>
4252<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4253value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4254<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4255
4256<h5>Semantics:</h5>
4257<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4258<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4259the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4260size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4261the size of a pointer then a zero extension is done. If they are the same size,
4262nothing is done (<i>no-op cast</i>).</p>
4263
4264<h5>Example:</h5>
4265<pre>
4266 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4267 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4268 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4269</pre>
4270</div>
4271
4272<!-- _______________________________________________________________________ -->
4273<div class="doc_subsubsection">
4274 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4275</div>
4276<div class="doc_text">
4277
4278<h5>Syntax:</h5>
4279<pre>
4280 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4281</pre>
4282
4283<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4285<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4286<tt>ty2</tt> without changing any bits.</p>
4287
4288<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4289
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4290<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4291a non-aggregate first class value, and a type to cast it to, which must also be
4292a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4293<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4294and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4295type is a pointer, the destination type must also be a pointer. This
4296instruction supports bitwise conversion of vectors to integers and to vectors
4297of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4298
4299<h5>Semantics:</h5>
4300<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4301<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4302this conversion. The conversion is done as if the <tt>value</tt> had been
4303stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4304converted to other pointer types with this instruction. To convert pointers to
4305other types, use the <a href="#i_inttoptr">inttoptr</a> or
4306<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4307
4308<h5>Example:</h5>
4309<pre>
4310 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4311 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4312 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4313</pre>
4314</div>
4315
4316<!-- ======================================================================= -->
4317<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4318<div class="doc_text">
4319<p>The instructions in this category are the "miscellaneous"
4320instructions, which defy better classification.</p>
4321</div>
4322
4323<!-- _______________________________________________________________________ -->
4324<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4325</div>
4326<div class="doc_text">
4327<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4328<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4329</pre>
4330<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4331<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4332a vector of boolean values based on comparison
4333of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4334<h5>Arguments:</h5>
4335<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4336the condition code indicating the kind of comparison to perform. It is not
4337a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4338</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4339<ol>
4340 <li><tt>eq</tt>: equal</li>
4341 <li><tt>ne</tt>: not equal </li>
4342 <li><tt>ugt</tt>: unsigned greater than</li>
4343 <li><tt>uge</tt>: unsigned greater or equal</li>
4344 <li><tt>ult</tt>: unsigned less than</li>
4345 <li><tt>ule</tt>: unsigned less or equal</li>
4346 <li><tt>sgt</tt>: signed greater than</li>
4347 <li><tt>sge</tt>: signed greater or equal</li>
4348 <li><tt>slt</tt>: signed less than</li>
4349 <li><tt>sle</tt>: signed less or equal</li>
4350</ol>
4351<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4352<a href="#t_pointer">pointer</a>
4353or integer <a href="#t_vector">vector</a> typed.
4354They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4355<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4356<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4357the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4358yields either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt> result, as follows:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4359</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4360<ol>
4361 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4362 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4363 </li>
4364 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4365 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4366 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4367 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4368 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4369 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4370 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4371 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4372 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4373 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4374 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4375 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4376 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4377 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4378 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4379 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4380 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4381 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4382</ol>
4383<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4384values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4385<p>If the operands are integer vectors, then they are compared
4386element by element. The result is an <tt>i1</tt> vector with
4387the same number of elements as the values being compared.
4388Otherwise, the result is an <tt>i1</tt>.
4389</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4390
4391<h5>Example:</h5>
4392<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4393 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4394 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4395 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4396 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4397 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4398</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4399
4400<p>Note that the code generator does not yet support vector types with
4401 the <tt>icmp</tt> instruction.</p>
4402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4403</div>
4404
4405<!-- _______________________________________________________________________ -->
4406<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4407</div>
4408<div class="doc_text">
4409<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4410<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4411</pre>
4412<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4413<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4414or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4415of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4416<p>
4417If the operands are floating point scalars, then the result
4418type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4419</p>
4420<p>If the operands are floating point vectors, then the result type
4421is a vector of boolean with the same number of elements as the
4422operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4423<h5>Arguments:</h5>
4424<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4425the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4426a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4427<ol>
4428 <li><tt>false</tt>: no comparison, always returns false</li>
4429 <li><tt>oeq</tt>: ordered and equal</li>
4430 <li><tt>ogt</tt>: ordered and greater than </li>
4431 <li><tt>oge</tt>: ordered and greater than or equal</li>
4432 <li><tt>olt</tt>: ordered and less than </li>
4433 <li><tt>ole</tt>: ordered and less than or equal</li>
4434 <li><tt>one</tt>: ordered and not equal</li>
4435 <li><tt>ord</tt>: ordered (no nans)</li>
4436 <li><tt>ueq</tt>: unordered or equal</li>
4437 <li><tt>ugt</tt>: unordered or greater than </li>
4438 <li><tt>uge</tt>: unordered or greater than or equal</li>
4439 <li><tt>ult</tt>: unordered or less than </li>
4440 <li><tt>ule</tt>: unordered or less than or equal</li>
4441 <li><tt>une</tt>: unordered or not equal</li>
4442 <li><tt>uno</tt>: unordered (either nans)</li>
4443 <li><tt>true</tt>: no comparison, always returns true</li>
4444</ol>
4445<p><i>Ordered</i> means that neither operand is a QNAN while
4446<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4447<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4448either a <a href="#t_floating">floating point</a> type
4449or a <a href="#t_vector">vector</a> of floating point type.
4450They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4451<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4452<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4453according to the condition code given as <tt>cond</tt>.
4454If the operands are vectors, then the vectors are compared
4455element by element.
4456Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4457always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4458<ol>
4459 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4460 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4461 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4462 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4463 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4464 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4465 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4466 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4467 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4468 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4469 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4470 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4471 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4472 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4473 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4474 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4475 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4476 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4477 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4478 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4479 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4480 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4481 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4482 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4483 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4484 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4485 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4486 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4487</ol>
4488
4489<h5>Example:</h5>
4490<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4491 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4492 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4493 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4494</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4495
4496<p>Note that the code generator does not yet support vector types with
4497 the <tt>fcmp</tt> instruction.</p>
4498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4499</div>
4500
4501<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4502<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4503 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4504</div>
4505
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4506<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4508<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4510<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4511<h5>Overview:</h5>
4512<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4513the SSA graph representing the function.</p>
4514<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4516<p>The type of the incoming values is specified with the first type
4517field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4518as arguments, with one pair for each predecessor basic block of the
4519current block. Only values of <a href="#t_firstclass">first class</a>
4520type may be used as the value arguments to the PHI node. Only labels
4521may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4523<p>There must be no non-phi instructions between the start of a basic
4524block and the PHI instructions: i.e. PHI instructions must be first in
4525a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4526
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4527<p>For the purposes of the SSA form, the use of each incoming value is
4528deemed to occur on the edge from the corresponding predecessor block
4529to the current block (but after any definition of an '<tt>invoke</tt>'
4530instruction's return value on the same edge).</p>
4531
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4532<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4534<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4535specified by the pair corresponding to the predecessor basic block that executed
4536just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4538<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4539<pre>
4540Loop: ; Infinite loop that counts from 0 on up...
4541 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4542 %nextindvar = add i32 %indvar, 1
4543 br label %Loop
4544</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4545</div>
4546
4547<!-- _______________________________________________________________________ -->
4548<div class="doc_subsubsection">
4549 <a name="i_select">'<tt>select</tt>' Instruction</a>
4550</div>
4551
4552<div class="doc_text">
4553
4554<h5>Syntax:</h5>
4555
4556<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4557 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
4558
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4559 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4560</pre>
4561
4562<h5>Overview:</h5>
4563
4564<p>
4565The '<tt>select</tt>' instruction is used to choose one value based on a
4566condition, without branching.
4567</p>
4568
4569
4570<h5>Arguments:</h5>
4571
4572<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4573The '<tt>select</tt>' instruction requires an 'i1' value or
4574a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4575condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4576type. If the val1/val2 are vectors and
4577the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4578individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4579</p>
4580
4581<h5>Semantics:</h5>
4582
4583<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4584If the condition is an i1 and it evaluates to 1, the instruction returns the first
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4585value argument; otherwise, it returns the second value argument.
4586</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4587<p>
4588If the condition is a vector of i1, then the value arguments must
4589be vectors of the same size, and the selection is done element
4590by element.
4591</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4592
4593<h5>Example:</h5>
4594
4595<pre>
4596 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4597</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4598
4599<p>Note that the code generator does not yet support conditions
4600 with vector type.</p>
4601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4602</div>
4603
4604
4605<!-- _______________________________________________________________________ -->
4606<div class="doc_subsubsection">
4607 <a name="i_call">'<tt>call</tt>' Instruction</a>
4608</div>
4609
4610<div class="doc_text">
4611
4612<h5>Syntax:</h5>
4613<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4614 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4615</pre>
4616
4617<h5>Overview:</h5>
4618
4619<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4620
4621<h5>Arguments:</h5>
4622
4623<p>This instruction requires several arguments:</p>
4624
4625<ol>
4626 <li>
4627 <p>The optional "tail" marker indicates whether the callee function accesses
4628 any allocas or varargs in the caller. If the "tail" marker is present, the
4629 function call is eligible for tail call optimization. Note that calls may
4630 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4631 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4632 </li>
4633 <li>
4634 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4635 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4636 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4637 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4638
4639 <li>
4640 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4641 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4642 and '<tt>inreg</tt>' attributes are valid here.</p>
4643 </li>
4644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4645 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4646 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4647 the type of the return value. Functions that return no value are marked
4648 <tt><a href="#t_void">void</a></tt>.</p>
4649 </li>
4650 <li>
4651 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4652 value being invoked. The argument types must match the types implied by
4653 this signature. This type can be omitted if the function is not varargs
4654 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4655 </li>
4656 <li>
4657 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4658 be invoked. In most cases, this is a direct function invocation, but
4659 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4660 to function value.</p>
4661 </li>
4662 <li>
4663 <p>'<tt>function args</tt>': argument list whose types match the
4664 function signature argument types. All arguments must be of
4665 <a href="#t_firstclass">first class</a> type. If the function signature
4666 indicates the function accepts a variable number of arguments, the extra
4667 arguments can be specified.</p>
4668 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4669 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4670 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4671 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4672 '<tt>readnone</tt>' attributes are valid here.</p>
4673 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4674</ol>
4675
4676<h5>Semantics:</h5>
4677
4678<p>The '<tt>call</tt>' instruction is used to cause control flow to
4679transfer to a specified function, with its incoming arguments bound to
4680the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4681instruction in the called function, control flow continues with the
4682instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4683function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4684
4685<h5>Example:</h5>
4686
4687<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4688 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4689 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4690 %X = tail call i32 @foo() <i>; yields i32</i>
4691 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4692 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4693
4694 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4695 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4696 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4697 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4698 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4699 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4700</pre>
4701
4702</div>
4703
4704<!-- _______________________________________________________________________ -->
4705<div class="doc_subsubsection">
4706 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4707</div>
4708
4709<div class="doc_text">
4710
4711<h5>Syntax:</h5>
4712
4713<pre>
4714 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4715</pre>
4716
4717<h5>Overview:</h5>
4718
4719<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4720the "variable argument" area of a function call. It is used to implement the
4721<tt>va_arg</tt> macro in C.</p>
4722
4723<h5>Arguments:</h5>
4724
4725<p>This instruction takes a <tt>va_list*</tt> value and the type of
4726the argument. It returns a value of the specified argument type and
4727increments the <tt>va_list</tt> to point to the next argument. The
4728actual type of <tt>va_list</tt> is target specific.</p>
4729
4730<h5>Semantics:</h5>
4731
4732<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4733type from the specified <tt>va_list</tt> and causes the
4734<tt>va_list</tt> to point to the next argument. For more information,
4735see the variable argument handling <a href="#int_varargs">Intrinsic
4736Functions</a>.</p>
4737
4738<p>It is legal for this instruction to be called in a function which does not
4739take a variable number of arguments, for example, the <tt>vfprintf</tt>
4740function.</p>
4741
4742<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4743href="#intrinsics">intrinsic function</a> because it takes a type as an
4744argument.</p>
4745
4746<h5>Example:</h5>
4747
4748<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4749
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4750<p>Note that the code generator does not yet fully support va_arg
4751 on many targets. Also, it does not currently support va_arg with
4752 aggregate types on any target.</p>
4753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4754</div>
4755
4756<!-- *********************************************************************** -->
4757<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4758<!-- *********************************************************************** -->
4759
4760<div class="doc_text">
4761
4762<p>LLVM supports the notion of an "intrinsic function". These functions have
4763well known names and semantics and are required to follow certain restrictions.
4764Overall, these intrinsics represent an extension mechanism for the LLVM
4765language that does not require changing all of the transformations in LLVM when
4766adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4767
4768<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4769prefix is reserved in LLVM for intrinsic names; thus, function names may not
4770begin with this prefix. Intrinsic functions must always be external functions:
4771you cannot define the body of intrinsic functions. Intrinsic functions may
4772only be used in call or invoke instructions: it is illegal to take the address
4773of an intrinsic function. Additionally, because intrinsic functions are part
4774of the LLVM language, it is required if any are added that they be documented
4775here.</p>
4776
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4777<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4778a family of functions that perform the same operation but on different data
4779types. Because LLVM can represent over 8 million different integer types,
4780overloading is used commonly to allow an intrinsic function to operate on any
4781integer type. One or more of the argument types or the result type can be
4782overloaded to accept any integer type. Argument types may also be defined as
4783exactly matching a previous argument's type or the result type. This allows an
4784intrinsic function which accepts multiple arguments, but needs all of them to
4785be of the same type, to only be overloaded with respect to a single argument or
4786the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4787
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4788<p>Overloaded intrinsics will have the names of its overloaded argument types
4789encoded into its function name, each preceded by a period. Only those types
4790which are overloaded result in a name suffix. Arguments whose type is matched
4791against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4792take an integer of any width and returns an integer of exactly the same integer
4793width. This leads to a family of functions such as
4794<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4795Only one type, the return type, is overloaded, and only one type suffix is
4796required. Because the argument's type is matched against the return type, it
4797does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4798
4799<p>To learn how to add an intrinsic function, please see the
4800<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4801</p>
4802
4803</div>
4804
4805<!-- ======================================================================= -->
4806<div class="doc_subsection">
4807 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4808</div>
4809
4810<div class="doc_text">
4811
4812<p>Variable argument support is defined in LLVM with the <a
4813 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4814intrinsic functions. These functions are related to the similarly
4815named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4816
4817<p>All of these functions operate on arguments that use a
4818target-specific value type "<tt>va_list</tt>". The LLVM assembly
4819language reference manual does not define what this type is, so all
4820transformations should be prepared to handle these functions regardless of
4821the type used.</p>
4822
4823<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4824instruction and the variable argument handling intrinsic functions are
4825used.</p>
4826
4827<div class="doc_code">
4828<pre>
4829define i32 @test(i32 %X, ...) {
4830 ; Initialize variable argument processing
4831 %ap = alloca i8*
4832 %ap2 = bitcast i8** %ap to i8*
4833 call void @llvm.va_start(i8* %ap2)
4834
4835 ; Read a single integer argument
4836 %tmp = va_arg i8** %ap, i32
4837
4838 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4839 %aq = alloca i8*
4840 %aq2 = bitcast i8** %aq to i8*
4841 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4842 call void @llvm.va_end(i8* %aq2)
4843
4844 ; Stop processing of arguments.
4845 call void @llvm.va_end(i8* %ap2)
4846 ret i32 %tmp
4847}
4848
4849declare void @llvm.va_start(i8*)
4850declare void @llvm.va_copy(i8*, i8*)
4851declare void @llvm.va_end(i8*)
4852</pre>
4853</div>
4854
4855</div>
4856
4857<!-- _______________________________________________________________________ -->
4858<div class="doc_subsubsection">
4859 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4860</div>
4861
4862
4863<div class="doc_text">
4864<h5>Syntax:</h5>
4865<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4866<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4867<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4868<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4869href="#i_va_arg">va_arg</a></tt>.</p>
4870
4871<h5>Arguments:</h5>
4872
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4873<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4874
4875<h5>Semantics:</h5>
4876
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4877<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4878macro available in C. In a target-dependent way, it initializes the
4879<tt>va_list</tt> element to which the argument points, so that the next call to
4880<tt>va_arg</tt> will produce the first variable argument passed to the function.
4881Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4882last argument of the function as the compiler can figure that out.</p>
4883
4884</div>
4885
4886<!-- _______________________________________________________________________ -->
4887<div class="doc_subsubsection">
4888 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4889</div>
4890
4891<div class="doc_text">
4892<h5>Syntax:</h5>
4893<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4894<h5>Overview:</h5>
4895
4896<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4897which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4898or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4899
4900<h5>Arguments:</h5>
4901
4902<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4903
4904<h5>Semantics:</h5>
4905
4906<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4907macro available in C. In a target-dependent way, it destroys the
4908<tt>va_list</tt> element to which the argument points. Calls to <a
4909href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4910<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4911<tt>llvm.va_end</tt>.</p>
4912
4913</div>
4914
4915<!-- _______________________________________________________________________ -->
4916<div class="doc_subsubsection">
4917 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4918</div>
4919
4920<div class="doc_text">
4921
4922<h5>Syntax:</h5>
4923
4924<pre>
4925 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4926</pre>
4927
4928<h5>Overview:</h5>
4929
4930<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4931from the source argument list to the destination argument list.</p>
4932
4933<h5>Arguments:</h5>
4934
4935<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4936The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4937
4938
4939<h5>Semantics:</h5>
4940
4941<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4942macro available in C. In a target-dependent way, it copies the source
4943<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4944intrinsic is necessary because the <tt><a href="#int_va_start">
4945llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4946example, memory allocation.</p>
4947
4948</div>
4949
4950<!-- ======================================================================= -->
4951<div class="doc_subsection">
4952 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4953</div>
4954
4955<div class="doc_text">
4956
4957<p>
4958LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4959Collection</a> (GC) requires the implementation and generation of these
4960intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4961These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4962stack</a>, as well as garbage collector implementations that require <a
4963href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4964Front-ends for type-safe garbage collected languages should generate these
4965intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4966href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4967</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4968
4969<p>The garbage collection intrinsics only operate on objects in the generic
4970 address space (address space zero).</p>
4971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4972</div>
4973
4974<!-- _______________________________________________________________________ -->
4975<div class="doc_subsubsection">
4976 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4977</div>
4978
4979<div class="doc_text">
4980
4981<h5>Syntax:</h5>
4982
4983<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4984 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4985</pre>
4986
4987<h5>Overview:</h5>
4988
4989<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4990the code generator, and allows some metadata to be associated with it.</p>
4991
4992<h5>Arguments:</h5>
4993
4994<p>The first argument specifies the address of a stack object that contains the
4995root pointer. The second pointer (which must be either a constant or a global
4996value address) contains the meta-data to be associated with the root.</p>
4997
4998<h5>Semantics:</h5>
4999
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5000<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5001location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5002the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5003intrinsic may only be used in a function which <a href="#gc">specifies a GC
5004algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5005
5006</div>
5007
5008
5009<!-- _______________________________________________________________________ -->
5010<div class="doc_subsubsection">
5011 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5012</div>
5013
5014<div class="doc_text">
5015
5016<h5>Syntax:</h5>
5017
5018<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5019 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5020</pre>
5021
5022<h5>Overview:</h5>
5023
5024<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
5025locations, allowing garbage collector implementations that require read
5026barriers.</p>
5027
5028<h5>Arguments:</h5>
5029
5030<p>The second argument is the address to read from, which should be an address
5031allocated from the garbage collector. The first object is a pointer to the
5032start of the referenced object, if needed by the language runtime (otherwise
5033null).</p>
5034
5035<h5>Semantics:</h5>
5036
5037<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
5038instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5039garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5040may only be used in a function which <a href="#gc">specifies a GC
5041algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5042
5043</div>
5044
5045
5046<!-- _______________________________________________________________________ -->
5047<div class="doc_subsubsection">
5048 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5049</div>
5050
5051<div class="doc_text">
5052
5053<h5>Syntax:</h5>
5054
5055<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5056 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5057</pre>
5058
5059<h5>Overview:</h5>
5060
5061<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
5062locations, allowing garbage collector implementations that require write
5063barriers (such as generational or reference counting collectors).</p>
5064
5065<h5>Arguments:</h5>
5066
5067<p>The first argument is the reference to store, the second is the start of the
5068object to store it to, and the third is the address of the field of Obj to
5069store to. If the runtime does not require a pointer to the object, Obj may be
5070null.</p>
5071
5072<h5>Semantics:</h5>
5073
5074<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
5075instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5076garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5077may only be used in a function which <a href="#gc">specifies a GC
5078algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5079
5080</div>
5081
5082
5083
5084<!-- ======================================================================= -->
5085<div class="doc_subsection">
5086 <a name="int_codegen">Code Generator Intrinsics</a>
5087</div>
5088
5089<div class="doc_text">
5090<p>
5091These intrinsics are provided by LLVM to expose special features that may only
5092be implemented with code generator support.
5093</p>
5094
5095</div>
5096
5097<!-- _______________________________________________________________________ -->
5098<div class="doc_subsubsection">
5099 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5100</div>
5101
5102<div class="doc_text">
5103
5104<h5>Syntax:</h5>
5105<pre>
5106 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5107</pre>
5108
5109<h5>Overview:</h5>
5110
5111<p>
5112The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5113target-specific value indicating the return address of the current function
5114or one of its callers.
5115</p>
5116
5117<h5>Arguments:</h5>
5118
5119<p>
5120The argument to this intrinsic indicates which function to return the address
5121for. Zero indicates the calling function, one indicates its caller, etc. The
5122argument is <b>required</b> to be a constant integer value.
5123</p>
5124
5125<h5>Semantics:</h5>
5126
5127<p>
5128The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5129the return address of the specified call frame, or zero if it cannot be
5130identified. The value returned by this intrinsic is likely to be incorrect or 0
5131for arguments other than zero, so it should only be used for debugging purposes.
5132</p>
5133
5134<p>
5135Note that calling this intrinsic does not prevent function inlining or other
5136aggressive transformations, so the value returned may not be that of the obvious
5137source-language caller.
5138</p>
5139</div>
5140
5141
5142<!-- _______________________________________________________________________ -->
5143<div class="doc_subsubsection">
5144 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5145</div>
5146
5147<div class="doc_text">
5148
5149<h5>Syntax:</h5>
5150<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5151 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5152</pre>
5153
5154<h5>Overview:</h5>
5155
5156<p>
5157The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5158target-specific frame pointer value for the specified stack frame.
5159</p>
5160
5161<h5>Arguments:</h5>
5162
5163<p>
5164The argument to this intrinsic indicates which function to return the frame
5165pointer for. Zero indicates the calling function, one indicates its caller,
5166etc. The argument is <b>required</b> to be a constant integer value.
5167</p>
5168
5169<h5>Semantics:</h5>
5170
5171<p>
5172The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5173the frame address of the specified call frame, or zero if it cannot be
5174identified. The value returned by this intrinsic is likely to be incorrect or 0
5175for arguments other than zero, so it should only be used for debugging purposes.
5176</p>
5177
5178<p>
5179Note that calling this intrinsic does not prevent function inlining or other
5180aggressive transformations, so the value returned may not be that of the obvious
5181source-language caller.
5182</p>
5183</div>
5184
5185<!-- _______________________________________________________________________ -->
5186<div class="doc_subsubsection">
5187 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5188</div>
5189
5190<div class="doc_text">
5191
5192<h5>Syntax:</h5>
5193<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5194 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5195</pre>
5196
5197<h5>Overview:</h5>
5198
5199<p>
5200The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5201the function stack, for use with <a href="#int_stackrestore">
5202<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5203features like scoped automatic variable sized arrays in C99.
5204</p>
5205
5206<h5>Semantics:</h5>
5207
5208<p>
5209This intrinsic returns a opaque pointer value that can be passed to <a
5210href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5211<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5212<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5213state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5214practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5215that were allocated after the <tt>llvm.stacksave</tt> was executed.
5216</p>
5217
5218</div>
5219
5220<!-- _______________________________________________________________________ -->
5221<div class="doc_subsubsection">
5222 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5223</div>
5224
5225<div class="doc_text">
5226
5227<h5>Syntax:</h5>
5228<pre>
5229 declare void @llvm.stackrestore(i8 * %ptr)
5230</pre>
5231
5232<h5>Overview:</h5>
5233
5234<p>
5235The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5236the function stack to the state it was in when the corresponding <a
5237href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5238useful for implementing language features like scoped automatic variable sized
5239arrays in C99.
5240</p>
5241
5242<h5>Semantics:</h5>
5243
5244<p>
5245See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5246</p>
5247
5248</div>
5249
5250
5251<!-- _______________________________________________________________________ -->
5252<div class="doc_subsubsection">
5253 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5254</div>
5255
5256<div class="doc_text">
5257
5258<h5>Syntax:</h5>
5259<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5260 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5261</pre>
5262
5263<h5>Overview:</h5>
5264
5265
5266<p>
5267The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5268a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5269no
5270effect on the behavior of the program but can change its performance
5271characteristics.
5272</p>
5273
5274<h5>Arguments:</h5>
5275
5276<p>
5277<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5278determining if the fetch should be for a read (0) or write (1), and
5279<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5280locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5281<tt>locality</tt> arguments must be constant integers.
5282</p>
5283
5284<h5>Semantics:</h5>
5285
5286<p>
5287This intrinsic does not modify the behavior of the program. In particular,
5288prefetches cannot trap and do not produce a value. On targets that support this
5289intrinsic, the prefetch can provide hints to the processor cache for better
5290performance.
5291</p>
5292
5293</div>
5294
5295<!-- _______________________________________________________________________ -->
5296<div class="doc_subsubsection">
5297 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5298</div>
5299
5300<div class="doc_text">
5301
5302<h5>Syntax:</h5>
5303<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5304 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5305</pre>
5306
5307<h5>Overview:</h5>
5308
5309
5310<p>
5311The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5312(PC) in a region of
5313code to simulators and other tools. The method is target specific, but it is
5314expected that the marker will use exported symbols to transmit the PC of the
5315marker.
5316The marker makes no guarantees that it will remain with any specific instruction
5317after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5318optimizations. The intended use is to be inserted after optimizations to allow
5319correlations of simulation runs.
5320</p>
5321
5322<h5>Arguments:</h5>
5323
5324<p>
5325<tt>id</tt> is a numerical id identifying the marker.
5326</p>
5327
5328<h5>Semantics:</h5>
5329
5330<p>
5331This intrinsic does not modify the behavior of the program. Backends that do not
5332support this intrinisic may ignore it.
5333</p>
5334
5335</div>
5336
5337<!-- _______________________________________________________________________ -->
5338<div class="doc_subsubsection">
5339 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5340</div>
5341
5342<div class="doc_text">
5343
5344<h5>Syntax:</h5>
5345<pre>
5346 declare i64 @llvm.readcyclecounter( )
5347</pre>
5348
5349<h5>Overview:</h5>
5350
5351
5352<p>
5353The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5354counter register (or similar low latency, high accuracy clocks) on those targets
5355that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5356As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5357should only be used for small timings.
5358</p>
5359
5360<h5>Semantics:</h5>
5361
5362<p>
5363When directly supported, reading the cycle counter should not modify any memory.
5364Implementations are allowed to either return a application specific value or a
5365system wide value. On backends without support, this is lowered to a constant 0.
5366</p>
5367
5368</div>
5369
5370<!-- ======================================================================= -->
5371<div class="doc_subsection">
5372 <a name="int_libc">Standard C Library Intrinsics</a>
5373</div>
5374
5375<div class="doc_text">
5376<p>
5377LLVM provides intrinsics for a few important standard C library functions.
5378These intrinsics allow source-language front-ends to pass information about the
5379alignment of the pointer arguments to the code generator, providing opportunity
5380for more efficient code generation.
5381</p>
5382
5383</div>
5384
5385<!-- _______________________________________________________________________ -->
5386<div class="doc_subsubsection">
5387 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5388</div>
5389
5390<div class="doc_text">
5391
5392<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5393<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5394width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5395<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5396 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5397 i8 &lt;len&gt;, i32 &lt;align&gt;)
5398 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5399 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5400 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5401 i32 &lt;len&gt;, i32 &lt;align&gt;)
5402 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5403 i64 &lt;len&gt;, i32 &lt;align&gt;)
5404</pre>
5405
5406<h5>Overview:</h5>
5407
5408<p>
5409The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5410location to the destination location.
5411</p>
5412
5413<p>
5414Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5415intrinsics do not return a value, and takes an extra alignment argument.
5416</p>
5417
5418<h5>Arguments:</h5>
5419
5420<p>
5421The first argument is a pointer to the destination, the second is a pointer to
5422the source. The third argument is an integer argument
5423specifying the number of bytes to copy, and the fourth argument is the alignment
5424of the source and destination locations.
5425</p>
5426
5427<p>
5428If the call to this intrinisic has an alignment value that is not 0 or 1, then
5429the caller guarantees that both the source and destination pointers are aligned
5430to that boundary.
5431</p>
5432
5433<h5>Semantics:</h5>
5434
5435<p>
5436The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5437location to the destination location, which are not allowed to overlap. It
5438copies "len" bytes of memory over. If the argument is known to be aligned to
5439some boundary, this can be specified as the fourth argument, otherwise it should
5440be set to 0 or 1.
5441</p>
5442</div>
5443
5444
5445<!-- _______________________________________________________________________ -->
5446<div class="doc_subsubsection">
5447 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5448</div>
5449
5450<div class="doc_text">
5451
5452<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5453<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5454width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5455<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5456 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5457 i8 &lt;len&gt;, i32 &lt;align&gt;)
5458 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5459 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5460 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5461 i32 &lt;len&gt;, i32 &lt;align&gt;)
5462 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5463 i64 &lt;len&gt;, i32 &lt;align&gt;)
5464</pre>
5465
5466<h5>Overview:</h5>
5467
5468<p>
5469The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5470location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5471'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5472</p>
5473
5474<p>
5475Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5476intrinsics do not return a value, and takes an extra alignment argument.
5477</p>
5478
5479<h5>Arguments:</h5>
5480
5481<p>
5482The first argument is a pointer to the destination, the second is a pointer to
5483the source. The third argument is an integer argument
5484specifying the number of bytes to copy, and the fourth argument is the alignment
5485of the source and destination locations.
5486</p>
5487
5488<p>
5489If the call to this intrinisic has an alignment value that is not 0 or 1, then
5490the caller guarantees that the source and destination pointers are aligned to
5491that boundary.
5492</p>
5493
5494<h5>Semantics:</h5>
5495
5496<p>
5497The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5498location to the destination location, which may overlap. It
5499copies "len" bytes of memory over. If the argument is known to be aligned to
5500some boundary, this can be specified as the fourth argument, otherwise it should
5501be set to 0 or 1.
5502</p>
5503</div>
5504
5505
5506<!-- _______________________________________________________________________ -->
5507<div class="doc_subsubsection">
5508 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5509</div>
5510
5511<div class="doc_text">
5512
5513<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5514<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5515width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5516<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5517 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5518 i8 &lt;len&gt;, i32 &lt;align&gt;)
5519 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5520 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5521 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5522 i32 &lt;len&gt;, i32 &lt;align&gt;)
5523 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5524 i64 &lt;len&gt;, i32 &lt;align&gt;)
5525</pre>
5526
5527<h5>Overview:</h5>
5528
5529<p>
5530The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5531byte value.
5532</p>
5533
5534<p>
5535Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5536does not return a value, and takes an extra alignment argument.
5537</p>
5538
5539<h5>Arguments:</h5>
5540
5541<p>
5542The first argument is a pointer to the destination to fill, the second is the
5543byte value to fill it with, the third argument is an integer
5544argument specifying the number of bytes to fill, and the fourth argument is the
5545known alignment of destination location.
5546</p>
5547
5548<p>
5549If the call to this intrinisic has an alignment value that is not 0 or 1, then
5550the caller guarantees that the destination pointer is aligned to that boundary.
5551</p>
5552
5553<h5>Semantics:</h5>
5554
5555<p>
5556The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5557the
5558destination location. If the argument is known to be aligned to some boundary,
5559this can be specified as the fourth argument, otherwise it should be set to 0 or
55601.
5561</p>
5562</div>
5563
5564
5565<!-- _______________________________________________________________________ -->
5566<div class="doc_subsubsection">
5567 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5568</div>
5569
5570<div class="doc_text">
5571
5572<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5573<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5574floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5575types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5576<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5577 declare float @llvm.sqrt.f32(float %Val)
5578 declare double @llvm.sqrt.f64(double %Val)
5579 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5580 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5581 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5582</pre>
5583
5584<h5>Overview:</h5>
5585
5586<p>
5587The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5588returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5589<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5590negative numbers other than -0.0 (which allows for better optimization, because
5591there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5592defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5593</p>
5594
5595<h5>Arguments:</h5>
5596
5597<p>
5598The argument and return value are floating point numbers of the same type.
5599</p>
5600
5601<h5>Semantics:</h5>
5602
5603<p>
5604This function returns the sqrt of the specified operand if it is a nonnegative
5605floating point number.
5606</p>
5607</div>
5608
5609<!-- _______________________________________________________________________ -->
5610<div class="doc_subsubsection">
5611 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5612</div>
5613
5614<div class="doc_text">
5615
5616<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5617<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5618floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5619types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5620<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5621 declare float @llvm.powi.f32(float %Val, i32 %power)
5622 declare double @llvm.powi.f64(double %Val, i32 %power)
5623 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5624 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5625 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5626</pre>
5627
5628<h5>Overview:</h5>
5629
5630<p>
5631The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5632specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5633multiplications is not defined. When a vector of floating point type is
5634used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5635</p>
5636
5637<h5>Arguments:</h5>
5638
5639<p>
5640The second argument is an integer power, and the first is a value to raise to
5641that power.
5642</p>
5643
5644<h5>Semantics:</h5>
5645
5646<p>
5647This function returns the first value raised to the second power with an
5648unspecified sequence of rounding operations.</p>
5649</div>
5650
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5651<!-- _______________________________________________________________________ -->
5652<div class="doc_subsubsection">
5653 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5654</div>
5655
5656<div class="doc_text">
5657
5658<h5>Syntax:</h5>
5659<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5660floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5661types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5662<pre>
5663 declare float @llvm.sin.f32(float %Val)
5664 declare double @llvm.sin.f64(double %Val)
5665 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5666 declare fp128 @llvm.sin.f128(fp128 %Val)
5667 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5668</pre>
5669
5670<h5>Overview:</h5>
5671
5672<p>
5673The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5674</p>
5675
5676<h5>Arguments:</h5>
5677
5678<p>
5679The argument and return value are floating point numbers of the same type.
5680</p>
5681
5682<h5>Semantics:</h5>
5683
5684<p>
5685This function returns the sine of the specified operand, returning the
5686same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5687conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5688</div>
5689
5690<!-- _______________________________________________________________________ -->
5691<div class="doc_subsubsection">
5692 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5693</div>
5694
5695<div class="doc_text">
5696
5697<h5>Syntax:</h5>
5698<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5699floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5700types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5701<pre>
5702 declare float @llvm.cos.f32(float %Val)
5703 declare double @llvm.cos.f64(double %Val)
5704 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5705 declare fp128 @llvm.cos.f128(fp128 %Val)
5706 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5707</pre>
5708
5709<h5>Overview:</h5>
5710
5711<p>
5712The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5713</p>
5714
5715<h5>Arguments:</h5>
5716
5717<p>
5718The argument and return value are floating point numbers of the same type.
5719</p>
5720
5721<h5>Semantics:</h5>
5722
5723<p>
5724This function returns the cosine of the specified operand, returning the
5725same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5726conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5727</div>
5728
5729<!-- _______________________________________________________________________ -->
5730<div class="doc_subsubsection">
5731 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5732</div>
5733
5734<div class="doc_text">
5735
5736<h5>Syntax:</h5>
5737<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5738floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5739types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5740<pre>
5741 declare float @llvm.pow.f32(float %Val, float %Power)
5742 declare double @llvm.pow.f64(double %Val, double %Power)
5743 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5744 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5745 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5746</pre>
5747
5748<h5>Overview:</h5>
5749
5750<p>
5751The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5752specified (positive or negative) power.
5753</p>
5754
5755<h5>Arguments:</h5>
5756
5757<p>
5758The second argument is a floating point power, and the first is a value to
5759raise to that power.
5760</p>
5761
5762<h5>Semantics:</h5>
5763
5764<p>
5765This function returns the first value raised to the second power,
5766returning the
5767same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5768conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5769</div>
5770
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5771
5772<!-- ======================================================================= -->
5773<div class="doc_subsection">
5774 <a name="int_manip">Bit Manipulation Intrinsics</a>
5775</div>
5776
5777<div class="doc_text">
5778<p>
5779LLVM provides intrinsics for a few important bit manipulation operations.
5780These allow efficient code generation for some algorithms.
5781</p>
5782
5783</div>
5784
5785<!-- _______________________________________________________________________ -->
5786<div class="doc_subsubsection">
5787 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5788</div>
5789
5790<div class="doc_text">
5791
5792<h5>Syntax:</h5>
5793<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5794type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5795<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5796 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5797 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5798 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5799</pre>
5800
5801<h5>Overview:</h5>
5802
5803<p>
5804The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5805values with an even number of bytes (positive multiple of 16 bits). These are
5806useful for performing operations on data that is not in the target's native
5807byte order.
5808</p>
5809
5810<h5>Semantics:</h5>
5811
5812<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5813The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5814and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5815intrinsic returns an i32 value that has the four bytes of the input i32
5816swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5817i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5818<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5819additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5820</p>
5821
5822</div>
5823
5824<!-- _______________________________________________________________________ -->
5825<div class="doc_subsubsection">
5826 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5827</div>
5828
5829<div class="doc_text">
5830
5831<h5>Syntax:</h5>
5832<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5833width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5834<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5835 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5836 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5837 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5838 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5839 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5840</pre>
5841
5842<h5>Overview:</h5>
5843
5844<p>
5845The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5846value.
5847</p>
5848
5849<h5>Arguments:</h5>
5850
5851<p>
5852The only argument is the value to be counted. The argument may be of any
5853integer type. The return type must match the argument type.
5854</p>
5855
5856<h5>Semantics:</h5>
5857
5858<p>
5859The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5860</p>
5861</div>
5862
5863<!-- _______________________________________________________________________ -->
5864<div class="doc_subsubsection">
5865 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5866</div>
5867
5868<div class="doc_text">
5869
5870<h5>Syntax:</h5>
5871<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5872integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5873<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5874 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5875 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5876 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5877 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5878 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5879</pre>
5880
5881<h5>Overview:</h5>
5882
5883<p>
5884The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5885leading zeros in a variable.
5886</p>
5887
5888<h5>Arguments:</h5>
5889
5890<p>
5891The only argument is the value to be counted. The argument may be of any
5892integer type. The return type must match the argument type.
5893</p>
5894
5895<h5>Semantics:</h5>
5896
5897<p>
5898The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5899in a variable. If the src == 0 then the result is the size in bits of the type
5900of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5901</p>
5902</div>
5903
5904
5905
5906<!-- _______________________________________________________________________ -->
5907<div class="doc_subsubsection">
5908 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5909</div>
5910
5911<div class="doc_text">
5912
5913<h5>Syntax:</h5>
5914<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5915integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5916<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5917 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5918 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5919 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5920 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5921 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5922</pre>
5923
5924<h5>Overview:</h5>
5925
5926<p>
5927The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5928trailing zeros.
5929</p>
5930
5931<h5>Arguments:</h5>
5932
5933<p>
5934The only argument is the value to be counted. The argument may be of any
5935integer type. The return type must match the argument type.
5936</p>
5937
5938<h5>Semantics:</h5>
5939
5940<p>
5941The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5942in a variable. If the src == 0 then the result is the size in bits of the type
5943of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5944</p>
5945</div>
5946
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5947
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5948<!-- ======================================================================= -->
5949<div class="doc_subsection">
5950 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5951</div>
5952
5953<div class="doc_text">
5954<p>
5955LLVM provides intrinsics for some arithmetic with overflow operations.
5956</p>
5957
5958</div>
5959
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5960<!-- _______________________________________________________________________ -->
5961<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5962 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5963</div>
5964
5965<div class="doc_text">
5966
5967<h5>Syntax:</h5>
5968
5969<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5970on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5971
5972<pre>
5973 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5974 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5975 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5976</pre>
5977
5978<h5>Overview:</h5>
5979
5980<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5981a signed addition of the two arguments, and indicate whether an overflow
5982occurred during the signed summation.</p>
5983
5984<h5>Arguments:</h5>
5985
5986<p>The arguments (%a and %b) and the first element of the result structure may
5987be of integer types of any bit width, but they must have the same bit width. The
5988second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
5989and <tt>%b</tt> are the two values that will undergo signed addition.</p>
5990
5991<h5>Semantics:</h5>
5992
5993<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5994a signed addition of the two variables. They return a structure &mdash; the
5995first element of which is the signed summation, and the second element of which
5996is a bit specifying if the signed summation resulted in an overflow.</p>
5997
5998<h5>Examples:</h5>
5999<pre>
6000 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6001 %sum = extractvalue {i32, i1} %res, 0
6002 %obit = extractvalue {i32, i1} %res, 1
6003 br i1 %obit, label %overflow, label %normal
6004</pre>
6005
6006</div>
6007
6008<!-- _______________________________________________________________________ -->
6009<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6010 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6011</div>
6012
6013<div class="doc_text">
6014
6015<h5>Syntax:</h5>
6016
6017<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6018on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6019
6020<pre>
6021 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6022 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6023 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6024</pre>
6025
6026<h5>Overview:</h5>
6027
6028<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6029an unsigned addition of the two arguments, and indicate whether a carry occurred
6030during the unsigned summation.</p>
6031
6032<h5>Arguments:</h5>
6033
6034<p>The arguments (%a and %b) and the first element of the result structure may
6035be of integer types of any bit width, but they must have the same bit width. The
6036second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6037and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6038
6039<h5>Semantics:</h5>
6040
6041<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6042an unsigned addition of the two arguments. They return a structure &mdash; the
6043first element of which is the sum, and the second element of which is a bit
6044specifying if the unsigned summation resulted in a carry.</p>
6045
6046<h5>Examples:</h5>
6047<pre>
6048 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6049 %sum = extractvalue {i32, i1} %res, 0
6050 %obit = extractvalue {i32, i1} %res, 1
6051 br i1 %obit, label %carry, label %normal
6052</pre>
6053
6054</div>
6055
6056<!-- _______________________________________________________________________ -->
6057<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6058 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6059</div>
6060
6061<div class="doc_text">
6062
6063<h5>Syntax:</h5>
6064
6065<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6066on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6067
6068<pre>
6069 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6070 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6071 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6072</pre>
6073
6074<h5>Overview:</h5>
6075
6076<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6077a signed subtraction of the two arguments, and indicate whether an overflow
6078occurred during the signed subtraction.</p>
6079
6080<h5>Arguments:</h5>
6081
6082<p>The arguments (%a and %b) and the first element of the result structure may
6083be of integer types of any bit width, but they must have the same bit width. The
6084second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6085and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6086
6087<h5>Semantics:</h5>
6088
6089<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6090a signed subtraction of the two arguments. They return a structure &mdash; the
6091first element of which is the subtraction, and the second element of which is a bit
6092specifying if the signed subtraction resulted in an overflow.</p>
6093
6094<h5>Examples:</h5>
6095<pre>
6096 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6097 %sum = extractvalue {i32, i1} %res, 0
6098 %obit = extractvalue {i32, i1} %res, 1
6099 br i1 %obit, label %overflow, label %normal
6100</pre>
6101
6102</div>
6103
6104<!-- _______________________________________________________________________ -->
6105<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6106 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6107</div>
6108
6109<div class="doc_text">
6110
6111<h5>Syntax:</h5>
6112
6113<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6114on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6115
6116<pre>
6117 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6118 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6119 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6120</pre>
6121
6122<h5>Overview:</h5>
6123
6124<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6125an unsigned subtraction of the two arguments, and indicate whether an overflow
6126occurred during the unsigned subtraction.</p>
6127
6128<h5>Arguments:</h5>
6129
6130<p>The arguments (%a and %b) and the first element of the result structure may
6131be of integer types of any bit width, but they must have the same bit width. The
6132second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6133and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6134
6135<h5>Semantics:</h5>
6136
6137<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6138an unsigned subtraction of the two arguments. They return a structure &mdash; the
6139first element of which is the subtraction, and the second element of which is a bit
6140specifying if the unsigned subtraction resulted in an overflow.</p>
6141
6142<h5>Examples:</h5>
6143<pre>
6144 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6145 %sum = extractvalue {i32, i1} %res, 0
6146 %obit = extractvalue {i32, i1} %res, 1
6147 br i1 %obit, label %overflow, label %normal
6148</pre>
6149
6150</div>
6151
6152<!-- _______________________________________________________________________ -->
6153<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6154 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6155</div>
6156
6157<div class="doc_text">
6158
6159<h5>Syntax:</h5>
6160
6161<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6162on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6163
6164<pre>
6165 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6166 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6167 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6168</pre>
6169
6170<h5>Overview:</h5>
6171
6172<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6173a signed multiplication of the two arguments, and indicate whether an overflow
6174occurred during the signed multiplication.</p>
6175
6176<h5>Arguments:</h5>
6177
6178<p>The arguments (%a and %b) and the first element of the result structure may
6179be of integer types of any bit width, but they must have the same bit width. The
6180second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6181and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6182
6183<h5>Semantics:</h5>
6184
6185<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6186a signed multiplication of the two arguments. They return a structure &mdash;
6187the first element of which is the multiplication, and the second element of
6188which is a bit specifying if the signed multiplication resulted in an
6189overflow.</p>
6190
6191<h5>Examples:</h5>
6192<pre>
6193 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6194 %sum = extractvalue {i32, i1} %res, 0
6195 %obit = extractvalue {i32, i1} %res, 1
6196 br i1 %obit, label %overflow, label %normal
6197</pre>
6198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6199</div>
6200
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6201<!-- _______________________________________________________________________ -->
6202<div class="doc_subsubsection">
6203 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6204</div>
6205
6206<div class="doc_text">
6207
6208<h5>Syntax:</h5>
6209
6210<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6211on any integer bit width.</p>
6212
6213<pre>
6214 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6215 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6216 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6217</pre>
6218
6219<h5>Overview:</h5>
6220
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6221<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6222a unsigned multiplication of the two arguments, and indicate whether an overflow
6223occurred during the unsigned multiplication.</p>
6224
6225<h5>Arguments:</h5>
6226
6227<p>The arguments (%a and %b) and the first element of the result structure may
6228be of integer types of any bit width, but they must have the same bit width. The
6229second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6230and <tt>%b</tt> are the two values that will undergo unsigned
6231multiplication.</p>
6232
6233<h5>Semantics:</h5>
6234
6235<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6236an unsigned multiplication of the two arguments. They return a structure &mdash;
6237the first element of which is the multiplication, and the second element of
6238which is a bit specifying if the unsigned multiplication resulted in an
6239overflow.</p>
6240
6241<h5>Examples:</h5>
6242<pre>
6243 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6244 %sum = extractvalue {i32, i1} %res, 0
6245 %obit = extractvalue {i32, i1} %res, 1
6246 br i1 %obit, label %overflow, label %normal
6247</pre>
6248
6249</div>
6250
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6251<!-- ======================================================================= -->
6252<div class="doc_subsection">
6253 <a name="int_debugger">Debugger Intrinsics</a>
6254</div>
6255
6256<div class="doc_text">
6257<p>
6258The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6259are described in the <a
6260href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6261Debugging</a> document.
6262</p>
6263</div>
6264
6265
6266<!-- ======================================================================= -->
6267<div class="doc_subsection">
6268 <a name="int_eh">Exception Handling Intrinsics</a>
6269</div>
6270
6271<div class="doc_text">
6272<p> The LLVM exception handling intrinsics (which all start with
6273<tt>llvm.eh.</tt> prefix), are described in the <a
6274href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6275Handling</a> document. </p>
6276</div>
6277
6278<!-- ======================================================================= -->
6279<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6280 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6281</div>
6282
6283<div class="doc_text">
6284<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6285 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6286 the <tt>nest</tt> attribute, from a function. The result is a callable
6287 function pointer lacking the nest parameter - the caller does not need
6288 to provide a value for it. Instead, the value to use is stored in
6289 advance in a "trampoline", a block of memory usually allocated
6290 on the stack, which also contains code to splice the nest value into the
6291 argument list. This is used to implement the GCC nested function address
6292 extension.
6293</p>
6294<p>
6295 For example, if the function is
6296 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6297 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6298<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6299 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6300 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6301 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6302 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6303</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6304 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6305 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6306</div>
6307
6308<!-- _______________________________________________________________________ -->
6309<div class="doc_subsubsection">
6310 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6311</div>
6312<div class="doc_text">
6313<h5>Syntax:</h5>
6314<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6315declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6316</pre>
6317<h5>Overview:</h5>
6318<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6319 This fills the memory pointed to by <tt>tramp</tt> with code
6320 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6321</p>
6322<h5>Arguments:</h5>
6323<p>
6324 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6325 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6326 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6327 intrinsic. Note that the size and the alignment are target-specific - LLVM
6328 currently provides no portable way of determining them, so a front-end that
6329 generates this intrinsic needs to have some target-specific knowledge.
6330 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6331</p>
6332<h5>Semantics:</h5>
6333<p>
6334 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6335 dependent code, turning it into a function. A pointer to this function is
6336 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6337 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6338 before being called. The new function's signature is the same as that of
6339 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6340 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6341 of pointer type. Calling the new function is equivalent to calling
6342 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6343 missing <tt>nest</tt> argument. If, after calling
6344 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6345 modified, then the effect of any later call to the returned function pointer is
6346 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6347</p>
6348</div>
6349
6350<!-- ======================================================================= -->
6351<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6352 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6353</div>
6354
6355<div class="doc_text">
6356<p>
6357 These intrinsic functions expand the "universal IR" of LLVM to represent
6358 hardware constructs for atomic operations and memory synchronization. This
6359 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6360 is aimed at a low enough level to allow any programming models or APIs
6361 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6362 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6363 hardware behavior. Just as hardware provides a "universal IR" for source
6364 languages, it also provides a starting point for developing a "universal"
6365 atomic operation and synchronization IR.
6366</p>
6367<p>
6368 These do <em>not</em> form an API such as high-level threading libraries,
6369 software transaction memory systems, atomic primitives, and intrinsic
6370 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6371 application libraries. The hardware interface provided by LLVM should allow
6372 a clean implementation of all of these APIs and parallel programming models.
6373 No one model or paradigm should be selected above others unless the hardware
6374 itself ubiquitously does so.
6375
6376</p>
6377</div>
6378
6379<!-- _______________________________________________________________________ -->
6380<div class="doc_subsubsection">
6381 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6382</div>
6383<div class="doc_text">
6384<h5>Syntax:</h5>
6385<pre>
6386declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6387i1 &lt;device&gt; )
6388
6389</pre>
6390<h5>Overview:</h5>
6391<p>
6392 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6393 specific pairs of memory access types.
6394</p>
6395<h5>Arguments:</h5>
6396<p>
6397 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6398 The first four arguments enables a specific barrier as listed below. The fith
6399 argument specifies that the barrier applies to io or device or uncached memory.
6400
6401</p>
6402 <ul>
6403 <li><tt>ll</tt>: load-load barrier</li>
6404 <li><tt>ls</tt>: load-store barrier</li>
6405 <li><tt>sl</tt>: store-load barrier</li>
6406 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6407 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6408 </ul>
6409<h5>Semantics:</h5>
6410<p>
6411 This intrinsic causes the system to enforce some ordering constraints upon
6412 the loads and stores of the program. This barrier does not indicate
6413 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6414 which they occur. For any of the specified pairs of load and store operations
6415 (f.ex. load-load, or store-load), all of the first operations preceding the
6416 barrier will complete before any of the second operations succeeding the
6417 barrier begin. Specifically the semantics for each pairing is as follows:
6418</p>
6419 <ul>
6420 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6421 after the barrier begins.</li>
6422
6423 <li><tt>ls</tt>: All loads before the barrier must complete before any
6424 store after the barrier begins.</li>
6425 <li><tt>ss</tt>: All stores before the barrier must complete before any
6426 store after the barrier begins.</li>
6427 <li><tt>sl</tt>: All stores before the barrier must complete before any
6428 load after the barrier begins.</li>
6429 </ul>
6430<p>
6431 These semantics are applied with a logical "and" behavior when more than one
6432 is enabled in a single memory barrier intrinsic.
6433</p>
6434<p>
6435 Backends may implement stronger barriers than those requested when they do not
6436 support as fine grained a barrier as requested. Some architectures do not
6437 need all types of barriers and on such architectures, these become noops.
6438</p>
6439<h5>Example:</h5>
6440<pre>
6441%ptr = malloc i32
6442 store i32 4, %ptr
6443
6444%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6445 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6446 <i>; guarantee the above finishes</i>
6447 store i32 8, %ptr <i>; before this begins</i>
6448</pre>
6449</div>
6450
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6451<!-- _______________________________________________________________________ -->
6452<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6453 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6454</div>
6455<div class="doc_text">
6456<h5>Syntax:</h5>
6457<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6458 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6459 any integer bit width and for different address spaces. Not all targets
6460 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6461
6462<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6463declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6464declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6465declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6466declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6467
6468</pre>
6469<h5>Overview:</h5>
6470<p>
6471 This loads a value in memory and compares it to a given value. If they are
6472 equal, it stores a new value into the memory.
6473</p>
6474<h5>Arguments:</h5>
6475<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6476 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6477 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6478 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6479 this integer type. While any bit width integer may be used, targets may only
6480 lower representations they support in hardware.
6481
6482</p>
6483<h5>Semantics:</h5>
6484<p>
6485 This entire intrinsic must be executed atomically. It first loads the value
6486 in memory pointed to by <tt>ptr</tt> and compares it with the value
6487 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6488 loaded value is yielded in all cases. This provides the equivalent of an
6489 atomic compare-and-swap operation within the SSA framework.
6490</p>
6491<h5>Examples:</h5>
6492
6493<pre>
6494%ptr = malloc i32
6495 store i32 4, %ptr
6496
6497%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6498%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6499 <i>; yields {i32}:result1 = 4</i>
6500%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6501%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6502
6503%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6504%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6505 <i>; yields {i32}:result2 = 8</i>
6506%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6507
6508%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6509</pre>
6510</div>
6511
6512<!-- _______________________________________________________________________ -->
6513<div class="doc_subsubsection">
6514 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6515</div>
6516<div class="doc_text">
6517<h5>Syntax:</h5>
6518
6519<p>
6520 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6521 integer bit width. Not all targets support all bit widths however.</p>
6522<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6523declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6524declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6525declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6526declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6527
6528</pre>
6529<h5>Overview:</h5>
6530<p>
6531 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6532 the value from memory. It then stores the value in <tt>val</tt> in the memory
6533 at <tt>ptr</tt>.
6534</p>
6535<h5>Arguments:</h5>
6536
6537<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6538 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6539 <tt>val</tt> argument and the result must be integers of the same bit width.
6540 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6541 integer type. The targets may only lower integer representations they
6542 support.
6543</p>
6544<h5>Semantics:</h5>
6545<p>
6546 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6547 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6548 equivalent of an atomic swap operation within the SSA framework.
6549
6550</p>
6551<h5>Examples:</h5>
6552<pre>
6553%ptr = malloc i32
6554 store i32 4, %ptr
6555
6556%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6557%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6558 <i>; yields {i32}:result1 = 4</i>
6559%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6560%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6561
6562%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6563%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6564 <i>; yields {i32}:result2 = 8</i>
6565
6566%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6567%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6568</pre>
6569</div>
6570
6571<!-- _______________________________________________________________________ -->
6572<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6573 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6574
6575</div>
6576<div class="doc_text">
6577<h5>Syntax:</h5>
6578<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6579 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on any
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6580 integer bit width. Not all targets support all bit widths however.</p>
6581<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6582declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6583declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6584declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6585declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6586
6587</pre>
6588<h5>Overview:</h5>
6589<p>
6590 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6591 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6592</p>
6593<h5>Arguments:</h5>
6594<p>
6595
6596 The intrinsic takes two arguments, the first a pointer to an integer value
6597 and the second an integer value. The result is also an integer value. These
6598 integer types can have any bit width, but they must all have the same bit
6599 width. The targets may only lower integer representations they support.
6600</p>
6601<h5>Semantics:</h5>
6602<p>
6603 This intrinsic does a series of operations atomically. It first loads the
6604 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6605 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6606</p>
6607
6608<h5>Examples:</h5>
6609<pre>
6610%ptr = malloc i32
6611 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6612%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6613 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6614%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6615 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6616%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6617 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6618%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6619</pre>
6620</div>
6621
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6622<!-- _______________________________________________________________________ -->
6623<div class="doc_subsubsection">
6624 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6625
6626</div>
6627<div class="doc_text">
6628<h5>Syntax:</h5>
6629<p>
6630 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6631 any integer bit width and for different address spaces. Not all targets
6632 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6633<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6634declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6635declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6636declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6637declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6638
6639</pre>
6640<h5>Overview:</h5>
6641<p>
6642 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6643 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6644</p>
6645<h5>Arguments:</h5>
6646<p>
6647
6648 The intrinsic takes two arguments, the first a pointer to an integer value
6649 and the second an integer value. The result is also an integer value. These
6650 integer types can have any bit width, but they must all have the same bit
6651 width. The targets may only lower integer representations they support.
6652</p>
6653<h5>Semantics:</h5>
6654<p>
6655 This intrinsic does a series of operations atomically. It first loads the
6656 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6657 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6658</p>
6659
6660<h5>Examples:</h5>
6661<pre>
6662%ptr = malloc i32
6663 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6664%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6665 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6666%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6667 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6668%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6669 <i>; yields {i32}:result3 = 2</i>
6670%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6671</pre>
6672</div>
6673
6674<!-- _______________________________________________________________________ -->
6675<div class="doc_subsubsection">
6676 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6677 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6678 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6679 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6680
6681</div>
6682<div class="doc_text">
6683<h5>Syntax:</h5>
6684<p>
6685 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6686 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6687 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6688 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6689<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6690declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6691declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6692declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6693declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6694
6695</pre>
6696
6697<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6698declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6699declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6700declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6701declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6702
6703</pre>
6704
6705<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6706declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6707declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6708declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6709declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6710
6711</pre>
6712
6713<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6714declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6715declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6716declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6717declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6718
6719</pre>
6720<h5>Overview:</h5>
6721<p>
6722 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6723 the value stored in memory at <tt>ptr</tt>. It yields the original value
6724 at <tt>ptr</tt>.
6725</p>
6726<h5>Arguments:</h5>
6727<p>
6728
6729 These intrinsics take two arguments, the first a pointer to an integer value
6730 and the second an integer value. The result is also an integer value. These
6731 integer types can have any bit width, but they must all have the same bit
6732 width. The targets may only lower integer representations they support.
6733</p>
6734<h5>Semantics:</h5>
6735<p>
6736 These intrinsics does a series of operations atomically. They first load the
6737 value stored at <tt>ptr</tt>. They then do the bitwise operation
6738 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6739 value stored at <tt>ptr</tt>.
6740</p>
6741
6742<h5>Examples:</h5>
6743<pre>
6744%ptr = malloc i32
6745 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6746%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6747 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6748%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6749 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6750%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6751 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6752%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6753 <i>; yields {i32}:result3 = FF</i>
6754%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6755</pre>
6756</div>
6757
6758
6759<!-- _______________________________________________________________________ -->
6760<div class="doc_subsubsection">
6761 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6762 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6763 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6764 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6765
6766</div>
6767<div class="doc_text">
6768<h5>Syntax:</h5>
6769<p>
6770 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6771 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6772 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6773 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6774 support all bit widths however.</p>
6775<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6776declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6777declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6778declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6779declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6780
6781</pre>
6782
6783<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6784declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6785declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6786declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6787declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6788
6789</pre>
6790
6791<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6792declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6793declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6794declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6795declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6796
6797</pre>
6798
6799<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6800declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6801declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6802declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6803declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6804
6805</pre>
6806<h5>Overview:</h5>
6807<p>
6808 These intrinsics takes the signed or unsigned minimum or maximum of
6809 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6810 original value at <tt>ptr</tt>.
6811</p>
6812<h5>Arguments:</h5>
6813<p>
6814
6815 These intrinsics take two arguments, the first a pointer to an integer value
6816 and the second an integer value. The result is also an integer value. These
6817 integer types can have any bit width, but they must all have the same bit
6818 width. The targets may only lower integer representations they support.
6819</p>
6820<h5>Semantics:</h5>
6821<p>
6822 These intrinsics does a series of operations atomically. They first load the
6823 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6824 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6825 the original value stored at <tt>ptr</tt>.
6826</p>
6827
6828<h5>Examples:</h5>
6829<pre>
6830%ptr = malloc i32
6831 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6832%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6833 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6834%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6835 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6836%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6837 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6838%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6839 <i>; yields {i32}:result3 = 8</i>
6840%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6841</pre>
6842</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6843
6844<!-- ======================================================================= -->
6845<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6846 <a name="int_general">General Intrinsics</a>
6847</div>
6848
6849<div class="doc_text">
6850<p> This class of intrinsics is designed to be generic and has
6851no specific purpose. </p>
6852</div>
6853
6854<!-- _______________________________________________________________________ -->
6855<div class="doc_subsubsection">
6856 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6857</div>
6858
6859<div class="doc_text">
6860
6861<h5>Syntax:</h5>
6862<pre>
6863 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6864</pre>
6865
6866<h5>Overview:</h5>
6867
6868<p>
6869The '<tt>llvm.var.annotation</tt>' intrinsic
6870</p>
6871
6872<h5>Arguments:</h5>
6873
6874<p>
6875The first argument is a pointer to a value, the second is a pointer to a
6876global string, the third is a pointer to a global string which is the source
6877file name, and the last argument is the line number.
6878</p>
6879
6880<h5>Semantics:</h5>
6881
6882<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6883This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6884This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6885annotations. These have no other defined use, they are ignored by code
6886generation and optimization.
6887</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6888</div>
6889
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6890<!-- _______________________________________________________________________ -->
6891<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6892 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6893</div>
6894
6895<div class="doc_text">
6896
6897<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6898<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6899any integer bit width.
6900</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6901<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6902 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6903 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6904 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6905 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6906 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6907</pre>
6908
6909<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6910
6911<p>
6912The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6913</p>
6914
6915<h5>Arguments:</h5>
6916
6917<p>
6918The first argument is an integer value (result of some expression),
6919the second is a pointer to a global string, the third is a pointer to a global
6920string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6921It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6922</p>
6923
6924<h5>Semantics:</h5>
6925
6926<p>
6927This intrinsic allows annotations to be put on arbitrary expressions
6928with arbitrary strings. This can be useful for special purpose optimizations
6929that want to look for these annotations. These have no other defined use, they
6930are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6931</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6932</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6933
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6934<!-- _______________________________________________________________________ -->
6935<div class="doc_subsubsection">
6936 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6937</div>
6938
6939<div class="doc_text">
6940
6941<h5>Syntax:</h5>
6942<pre>
6943 declare void @llvm.trap()
6944</pre>
6945
6946<h5>Overview:</h5>
6947
6948<p>
6949The '<tt>llvm.trap</tt>' intrinsic
6950</p>
6951
6952<h5>Arguments:</h5>
6953
6954<p>
6955None
6956</p>
6957
6958<h5>Semantics:</h5>
6959
6960<p>
6961This intrinsics is lowered to the target dependent trap instruction. If the
6962target does not have a trap instruction, this intrinsic will be lowered to the
6963call of the abort() function.
6964</p>
6965</div>
6966
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6967<!-- _______________________________________________________________________ -->
6968<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6969 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6970</div>
6971<div class="doc_text">
6972<h5>Syntax:</h5>
6973<pre>
6974declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6975
6976</pre>
6977<h5>Overview:</h5>
6978<p>
6979 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6980 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6981 it is placed on the stack before local variables.
6982</p>
6983<h5>Arguments:</h5>
6984<p>
6985 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6986 first argument is the value loaded from the stack guard
6987 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6988 has enough space to hold the value of the guard.
6989</p>
6990<h5>Semantics:</h5>
6991<p>
6992 This intrinsic causes the prologue/epilogue inserter to force the position of
6993 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6994 stack. This is to ensure that if a local variable on the stack is overwritten,
6995 it will destroy the value of the guard. When the function exits, the guard on
6996 the stack is checked against the original guard. If they're different, then
6997 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6998</p>
6999</div>
7000
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7001<!-- *********************************************************************** -->
7002<hr>
7003<address>
7004 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7005 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7006 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7007 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7008
7009 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7010 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7011 Last modified: $Date$
7012</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7013
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7014</body>
7015</html>